Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1995-1999  (140)
  • 1975-1979
  • 1920-1924
  • 1998  (140)
  • Capillary electrophoresis  (140)
  • 1
    Electronic Resource
    Electronic Resource
    Sample preparation for photometric determination of histamine in foodstuffs compared with capillary electrophoresis (1998)
    Springer
    Zeitschrift für Lebensmittel-Untersuchung und -Forschung 206 (1998), S. 246-250 
    Details
    ISSN: 1431-4630
    Keywords: Key words Histamine ; Capillary electrophoresis ; Photometric determination ; Liquid liquid extraction ; Solid phase extraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract  To determine levels of histamine, two methods were used, photometry in conjunction with two sample clean-up procedures, and capillary zone electrophoresis (CZE). The two sample clean-up procedures used were liquid liquid extraction (LLE) with n-butanol and solid phase extraction (SPE). Using CZE, the separation of histamine from the matrix was good. The other method, photometry, represents a classic and simple method, that can be employed for in situ measurement of histamine. We found that it was necessary to clean up the samples prior to photometry; if this was not done, the recorded levels of histamine were higher than those determined by CZE. In order to determine levels of histamine, both of these rapid tests were applied to ten different foodstuffs. The levels of histamine measured using photometry following either LLE or SPE were compared. The results indicated that photometry is a suitable method for the measurement of histamine, although the sample solutions have to be purified by either LLE or SPE. Samples do not need to be cleaned up before CZE because there is no interference between histamine and attendant material. Both sample clean-up procedures were applied to the following foodstuffs: tomatoes, sauerkraut, tuna, leaf spinach, cream spinach, white wine and mackerel. The differences of the measured values vary between 3% and 18% for LLE and 6% and 27% for SPE. For the other foodstuffs, such as beef, beer and non-alcoholic beer, only one sample clean-up procedure is suitable. LLE used for beef and beer leads to differences in measured levels of histamine between 18% and 50%, respectively, whereas SPE used for non-alcoholic beer leads to differences of 20%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002170050252
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Characterization of humic-like substances in airborne particulate matter by capillary electrophoresis (1998)
    Springer
    Chromatographia 47 (1998), S. 619-624 
    Details
    ISSN: 1612-1112
    Keywords: Capillary electrophoresis ; Airborne particles ; Humic-like substances
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A considerable fraction of the refractory organic carbon in airborne particulate matter is to be attributed to humic-like substances (HULIS). Such atmospheric HULIS isolated from different air dust samples by a microscale extraction procedure were characterized by capillary electrophoresis (CE). For fractionation of HULIS the working conditions of the CE system were optimized using a borate buffer (pH 8.2), polyacrylamide (PAA) coated, fused-silica capillary and polyethylene glycol as sieving modifier. Using CE under optimized conditions, HULIS produced electropherograms showing well resolved and reproducible signals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02467443
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    High-performance capillary electrophoretic analysis of synthetic food colorants (1998)
    Springer
    Chromatographia 47 (1998), S. 249-256 
    Details
    ISSN: 1612-1112
    Keywords: Capillary electrophoresis ; Cyclodextrin mobile phase additives ; Synthetic food colorants ; Selectivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A high-performance capillary electrophoresis method with diode-array detection has been developed for analysis of synthetic food colorants. The influence of buffer composition on the separation of the food colorants was examined, as were the effects of α-, β- and γ-c-yclodextrins on analyte migration behavior. Eight food colorants were completely separated within 10 min using pH 9.5 borax—NaOH buffer containing 5 mM β-cyclodextrin. Experimental results indicate that the relative standard deviations of analyte migration times were〈0.88% under the optimized separation condition. Correlation coefficients of the linear calibration plots of the analytes exceeded 0.998. The method was suitable for determination of the quantities of synthetic food colorantsi in ice cream bars and fruit soda drinks.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02466528
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Effects of buffer depletion in capillary electrophoresis: Development of a continuous flow cathode (1998)
    Springer
    Chromatographia 48 (1998), S. 355-359 
    Details
    ISSN: 1612-1112
    Keywords: Capillary electrophoresis ; Cathodic flow electrode ; Electrolyte buffer depletion ; Reproductibility and precision
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The effects of electrolyte buffer depletion is well recognised and regular replacement of the electrolyte can prevent poor reproducibility. We have further investigated the effect of electrolyte depletion and produced a modified cathodic flow electrode to improve reproducibility using minimal volumes of electrolytes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02467703
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Experimental design methodologies to optimize the CE separation of epinephrine enantiomers (1998)
    Springer
    Chromatographia 48 (1998), S. 395-401 
    Details
    ISSN: 1612-1112
    Keywords: Capillary electrophoresis ; Enantiomers ; Epinephrine ; Experimental designs ; Optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A capillary electrophoretic method using a chiral selector was optimized by experimental design for the enantioresolution of epinephrine enantiomers. Two β-cyclodextrins derivatives, namely heptakis-2,6-di-O-methyl-β-cyclodextrin and carboxy-methyl-β-cyclodextrin, respectively neutral and charged, were used as chiral selectors employing an uncoated capillary. By using a statistical experimental design in which all factors are varied at the same time, it was possible to optimize the method with regard to the resolution between peaks and the two migration times. A fractional factorial design and a central composite design were used. A compromise between conflicting goals, such as maximization of resolution and minimization of analysis time, was found by means of a desirability function D. Balancing these goals against each other, the most acceptable solution to the problem was found and the optimized method gave a fast separation with complete resolution between the adrenaline enantiomers. The response surfaces obtained confirmed the robustness of the method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02467710
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Determination of weak (2.0–2.5) dissociation constants of non-UV absorbing solutes by capillary electrophoresis (1998)
    Springer
    Chromatographia 48 (1998), S. 529-534 
    Details
    ISSN: 1612-1112
    Keywords: Capillary electrophoresis ; pK A determination ; Indirect UV detection ; Alkyl-alkyl phosphonic acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Capillary electrophoresis (CE) has proved to be a fast and convenient method for the determination of the dissociation constants of non-UV absorbing solutes in the acidic pK A range (2.0–2.5). The electroosmotic flow was reversed by washing the capillary with 0.2% polybren aqueous solution. A series of background electrolytes was prepared with phenylphosphonic acid (pK A=1.29) and β-alanine (pK A=3.55) with the same ionic strength and a high buffer capacity in order to improve the repeatability (0.1–0.2 %) of the electrophoretic mobility and to determine the values of pK A accurately. This procedure was applied to the determination of the dissociation constants of several alkyl-alkylphosphonic acids whose pK A values have not yet been published in the literature. In this work, their dissociation constants have been found to vary between 1.91 and 2.34 for alkyl-methylphosphonic acids and between 2.10 and 2.38 for alkyl-ethylphosphonic acids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02466645
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Determination of aldehydes in water samples by capillary electrophoresis after derivatization with hydrazino benzene sulfonic acid (1998)
    Springer
    Chromatographia 48 (1998), S. 807-810 
    Details
    ISSN: 1612-1112
    Keywords: Capillary electrophoresis ; Aldehydes ; Hydrazino benzene sulfonic acid ; Water analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A method has been developed for the analysis of environmentally important aldehydes in rain water. The method is based on the derivatization of the aldehydes with hydrazino benzene sulfonic acid, separation of the hydrazones formed by capillary electrophoresis and UV detection at 280 nm. Derivatization was shown to be complete in 15 min at 50°C. The aldehyde derivatives could be separated from each other and from the excess of reagent using a pH 9 borate buffer as background electrolyte, with an analysis time of less than 6 min. The repeatability was better than 0.5% for the peak mobilities and in the order of 2–5% for the peak areas. Detection limits of 0.8–3 μmol L−1 (0.02–0.2 ppm) were obtained. The method was applied for the determination of formaldehyde and acetaldehyde in rain water samples.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02467652
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Capillary gel electrophoresis of oligonucleotides using polymer solutions (1998)
    Springer
    Chromatographia 48 (1998), S. 569-575 
    Details
    ISSN: 1612-1112
    Keywords: Capillary electrophoresis ; Oligonucleotides ; Dextran ; Polymer solution ; Purity testing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Capillary gel electrophoresis (CGE) has been recognized as an effective method for the analysis of oligonucleotides. CGE using polymer solutions is especially useful and effective compared with that using crosslinked gels, because of easy change of media. Replacement of media leads to the reproducible separation of analytes. We have investigated CGE analysis of oligonucleotides of less than 20 bases employing various kinds of polymers. Polyacrylamide, dextrin, dextran, pullakin, and poly(ethylene glycol) were used as sieving matrixes at concentrations of 0–30 %. Polydeoxythymidylic acids [p(dT)11–20] were used as a test sample. These small oligonucleotides were successfully resolved on the basis of their base number by CGE using some of these polymer solutions. In particular, dextran was found to be effective and baseline separation was observed when a 30 % dextran solution was employed. Some validations such as linearity and reproducibility were also established and this method was found to be an adequate quality control method for small oligonucleotides. Finally, CGE using a 30 % dextran solution was successfully applied to impurity profiling of some synthetic oligonucleotides.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02466651
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Capillary electrophoretic study of the complexation of nucleotides with magnesium and calcium ions (1998)
    Springer
    Chromatographia 48 (1998), S. 739-744 
    Details
    ISSN: 1612-1112
    Keywords: Capillary electrophoresis ; Nucleotides ; Inorganic cations ; Complexation with Mg and Ca
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The complexation equilibrium between nucleotides (ATP, ADP) and inorganic cations (Mg2+, Ca2+) has been studied by capillary electrophoresis. The equilibrium constant and the stoichiometry of nucleotide-inorganic cation complexes can be deduced from the dependence of the electrophoretic mobility of each nucleotide on the negative logarithm of the inorganic cation concentration. The experimental values of complexation constants determined by CE compare favorably with those in the literature. As expected, Mg2+ forms more stable complexes with ATP (logK=2.30 and 4.10 at pH 5 and 8, respectively) than with ADP (logK=1.92 and 3.15 at pH 5 and 8, respectively). In the pH range 4–8, the stoichiometry of ADP-Mg2+ and ADP-Ca2+ complexes is always 1∶1 whereas that of the complexes between these cations and ATP depends on pH-hence ATP-Mg2+ and ATP-Ca2+ complexes have 1∶1 stoichiometry at pH 5 and 1∶2 at pH 8.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02467641
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    The effect of conductivity tuning in chiral separations by CE; Using hydroxypropyl-β-cyclodextrin in combination with tetraalkylammonium ions (1998)
    Springer
    Chromatographia 48 (1998), S. 415-421 
    Details
    ISSN: 1612-1112
    Keywords: Capillary electrophoresis ; Conductivity tuning ; Chiral separation ; Peak symmetry ; Resolution expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Different approaches how to handle the electromigration dispersion process that occurs in separation and determination of enantiomers are presented. The use of cyclodextrins as chiral selectors in resolution enantiomers involves the possibility to tune the conductivity of the sample band in order to obtain symmetrical and efficient peaks. Determination of impurities that migrate in the rear part of an overloaded main peak can be accomplished if the conductivity of the background electrolyte (BGE) is adapted to the conductivity of the sample band. This strategy was shown in determination of the content of D-sotalol in a mixture of L and D-sotalol. The efficiency and the symmetry of the overloaded L-sotalol peak was substantially improved by substitution of tetrabutylammonium ions for tetrapentylammonium ions as co-ions in the BGE. In this system it was possible to determine 0.2% w/w of the chiral impurity D-sotalol. A resolution model is presented and used qualitatively in the study where the complexation between the tetraalkyllammonium ions and the cyclodextrins is taken into account.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02467713
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 11
    Electronic Resource
    Electronic Resource
    A standard addition method for the quantitative determination of succinic acid and levulinic acid in processed acid stream extracts employing indirect UV capillary electrophoresis (1998)
    Springer
    Chromatographia 47 (1998), S. 709-715 
    Details
    ISSN: 1612-1112
    Keywords: Capillary electrophoresis ; Succinic and levulinic acid ; Indirect UV detection ; Standard addition method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary This paper describes an capillary electrophoresis (CE) method used to quantify both succinic acid and levulinic acid in an industrial production process. Measurement was performed by CE with indirect UV detection, using potassium hydrogen phthalate as the UV-absorbing additive. The electrolyte composition used was 5 mM potassium hydrogen phthalate at pH 7.0 containing 0.25 mM cetyl trimethylammonium bromide (CTAB) as an electrosmotic flow (EOF) modifier to reverse the EOF. The method provides for improved sensitivity by employing an extended path length capillary, and for identification and quantification by the use of a standard addition method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02467458
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    Capillary zone electrophoretic separation of basic proteins and drugs using guaran as a buffer modifier (1998)
    Springer
    Chromatographia 47 (1998), S. 219-224 
    Details
    ISSN: 1612-1112
    Keywords: Capillary electrophoresis ; Beta-blockers ; Protein separation ; Drug separation ; Guaran ; Buffer modifier
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Guaran, a neutral polysaccharide, has been used as a buffer modifier to improve the separation of basic proteins and drugs. Migration reproductibility, peak shape and efficiency were improved when 0.1% guaran was added to the buffer. The concentration of guaran, ionic strength, and pH of buffer solution were optimized to obtain the optimum separation of proteins. Possible separation efficiencies of 700,000 plates per meter were obtained for test proteins. The relative standard deviation (% RSD) of the migration time of all test proteins was less than 0.5%. Improved separation of β-blockers was also observed when guaran was added to the buffer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02466585
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    Rapid and reproducible capillary electrophoretic separation of double-stranded DNA fragments in a simple methyl cellulosic sieving system (1998)
    Springer
    Chromatographia 47 (1998), S. 125-134 
    Details
    ISSN: 1612-1112
    Keywords: Capillary electrophoresis ; DNA fragments ; Cellulose derivatives ; Sieving cellulose matrix
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A rapid, robust and reproducible method providing excellent separation performance and simplicity using a 0.5% MC-4000 methyl cellulosic sieving medium in DB-1 coated capillaries has been developed. The method is suitable for qualitative comparison of DNA restriction profiles for fragments in the size range 100–1000 base pairs (bp). Efficiencies up to 8.5 million plates/m (1057 bp fragment) were recorded. Peak resolution of 6 bp (291/297 bp, 335/341 bp) and 4 bp (238/242 bp, 341/345 bp) was achieved. In addition, 1 bp partial resolution of 123/124 bp and 298/297 bp was obtained. Run-to-run (n=15), day-to-day (n=4), and capillary-to-capillary (n=3) variations of 0.1–0.2% RSD, 0.3–0.5% RSD, and 0.1–0.3% RSD, respectively, were observed. The MC-4000 sieving matrix was found to be better than hydroxypropyl methyl cellulose and hydroxypropyl cellulose, in terms of both performance and stability in the DB-1 coated capillaries. The efficiency and resolution in DB-WAX capillaries were inferior to those obtained in DB-1 capillaries. The commercially available DB-1 capillaries were stable for months in the sieving medium at pH 8.3 and could be regenerated to provide high efficiency after accidental current breaks.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02466571
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    Peak recognition imitating human judgement (1998)
    Springer
    Chromatographia 48 (1998), S. 331-346 
    Details
    ISSN: 1612-1112
    Keywords: Peak integration ; Baseline determination ; Quantitation ; Capillary electrophoresis ; Chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Peak integration is still a major source of error in analytical techniques such as chromatography (LC and GC), aapillary electrophoresis (CE), spectrosocpy, and electrochemistry. If the baseline is complex, e.g. because of matrix effects, or if the peak shape is irregular, e.g. because of peak tailing, the results are often not satisfactory when classical procedures are used. These shortcomings arise because of the stepwise appearance of the chromatogram. An algorithm that copies the human method of considering baseline and peaks as a whole has already been introduced. Here the use of a straight line as a baseline model led to an improvement in several instances. The baseline is, however, usually not exactly straight and rigid. A baseline model with flexible properties is more advantageous. Thus the smoothing cubic spline function is applied in this work. Here the rigidity can be controlled by use of a parameterp k. The prediction interval of the spline is used for iterative distinction between baseline and peak regions. Afterwards straightforward optimization of the peak boundaries is applied. More than 50 series of consecutive injections of the same sample (n=40 on average) were used to test the performance of this procedure. The same raw data have been integrated by means of the algorithm described here and by use of commercially available software. The reproducibility of the main component peak are within the series was taken as a measure of integration quality. Typically the new procedure reducesRSD % by approximately 33% (e.g. from 1.5% to 1.0%). The improvement is even more impressive for difficult samples with complex matrices, e.g. blood plasma or polymer excipients. for such samples improvements of up to a factor of 6 are obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02467701
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    Capillary electrophoresis analysis of isomeric truxillines and other high molecular weight impurities in illicit cocaine (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 51-56 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Truxillines ; Cocaine ; Cyclodextrins ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The analysis of by-products and impurities in illicit cocaine, including the isomeric truxillines, is important for derivation of both strategic and tactical intelligence. In the present study, various capillary electrophoresis techniques were investigated for this purpose. The use of the anionic β-cyclodextrin sulfobutyl ether IV as a run buffer additive at pH 8.6 gave a good separation of the truxillines and similar high molecular weight impurities in less than eight minutes. These impurities were first isolated from the bulk cocaine matrix using liquid-liquid extraction and size-exclusion high performance liquid chromatography. There was a red shift in the UV spectra obtained for the truxillines using photodiode array (PDA) UV detection during CE analysis. This anomalous behavior is attributed to photo-degradation of the truxillines during the PDA-UV irradiation process. Laser-induced fluorescence detection using a UV krypton/fluoride laser provided greater selectivity and sensitivity versus UV detection for certain uncharacterized high molecular weight impurities.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190110
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    Capillary ion analysis of potassium concentrations in human vitreous humor (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 6-10 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Vitreous humor ; Potassium ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Capillary ion analysis (CIA) is a form of capillary electrophoresis which uses the differential electrophoretic mobility of ions to perform a separation of an ionic mixture. Application of this technique for direct detection of potassium concentrations in human vitreous humor was the purpose of this investigation. CIA was performed using a Waters Quanta 4000 Capillary Electrophoresis System with a 745 Data Module using a 75 μm × 60 cm capillary and a run electrolyte of 67.7 mg hydroxyisobutyric acid (HIBA), 52.8 mg 18-crown-6 ether and 64 μL UV-CAT-1 reagent (4-ethylbenzylamine) in a volume of 100 mL water (18 Mohm) with a voltage of 20 kV using ultraviolet absorption detection at 214 nm. Migration times were: ammonium ion, 2.86 min; potassium, 3.24 min; calcium, 3.84 min; sodium, 3.98 min; barium (internal standard), 4.68 min; and lithium, 4.79 min. Correlation coefficients (r) between peak area ratios and concentration ranges of 2.5-144 mmole/L (100-1000 ppm) were from 0.9855 to 0.9999. Coefficients of variation (CV) ranged from 1.45 to 13.8% between days and from 1.38 to 9.43% within-day. Application of this methodology to twenty-five vitreous humor specimens from forensic cases was compared to analysis by ion-specific electrode for potassium concentration. Comparison of CIA to ion-specific electrode analysis of vitreous humor potassium concentrations revealed a correlation coefficient of 0.9642. CIA is applicable to forensic analysis of potassium concentration in forensic vitreous humor specimens. Quantitation of numerous cation concentrations is possible by direct CIA of vitreous humor.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190104
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    Capillary sample introduction of polymerase chain reaction (PCR) products separated in ultrathin slab gels (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 71-75 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Ultrathin slab gels ; Polymerase chain reaction products ; Parallel separations ; Forensic analysis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Polymerase chain reaction (PCR) amplified short tandem repeat (STR) samples from the HUMVWF locus have been analyzed using a unique sample introduction and separation technique. A single capillary is used to transfer samples onto an ultrathin slab gel (57 μm thin). This ultrathin nondenaturing polyacrylamide gel is used to separate the amplified fragments, and laser-induced fluorescence with ethidium bromide is used for detection. The feasibility of performing STR analysis using this system has been investigated by examining the reproducibility for repeated samples. Reproducibility is examined by comparing the migration of the 14 and 17 HUMVWF alleles on three consecutive separations on the ultrathin slab gel. Using one locus, separations match in migration time with the two alleles 42s apart for each of the three consecutive separations. This technique shows potential to increase sample throughput in STR techniques although separation resolution still needs to be improved.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190113
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    Analysis of two multiplexed short tandem repeat systems using capillary electrophoresis with multiwavelength fluorescence detection (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 94-100 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Hydroxyethylcellulose ; DNA ; Polymerase chain reaction ; Fluorescence ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: A series of experiments was performed to analyze the utility of capillary electrophoresis (CE) with multiwavelength detection capabilities for multiplex typing of short tandem repeat loci. Characteristics of the sieving polymer, hydroxyethylcellulose, which affect resolution of single strand (ss) DNA fragments were examined. Additionally, the effects of denaturant in the polymer system, separation voltage, and analysis temperature were studied to ascertain their effects on DNA separations and capillary lifetime. The use of elevated run temperature (60°C) was found to improve sizing precision, to increase the lifetime of capillaries (100 runs or more per capillary), and to provide runtimes of under 20 min. Finally, 100 individual human DNA samples were typed successfully using CE. The average resolution obtained was 1.4 bases for a 200 base fragment with a standard deviation of sizing of 0.2 bases, allowing all alleles examined to be distinguished clarlyPresented in part at the 7th Annual Frederick Conference on Capillary Electrophoresis. Frederick, MD, USA, October 21-23, 1996.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190117
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    Using capillary electrophoresis/frontal analysis to screen drugs interacting with human serum proteins (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 448-454 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Frontal analysis ; Serum protein binding ; β-Blockers ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: We have used capillary electrophoresis in the frontal analysis mode (CE/FA) to determine the binding capacity of β-adrenoceptor blocking drugs to individual serum proteins, serum protein mixtures and human serum. The free drug concentration was directly measured from the height of the frontal peak and used to calculate the bound drug concentration. From the bound drug concentration, the percentage of drug bound to the serum proteins α1-acid glycoprotein (AGP) and human serum albumin (HSA) was then determined. In addition to determining the percent of a drug bound to a protein, the drug-protein association constant (Ka) was determined for AGP binding to β-blockers. The data-estimated association constants were consistent with literature values. The CE/FA studies on the β-adrenoceptor blocking drugs and the serum proteins indicated that HSA, AGP, high density lipoprotein (HDL), and low density lipoprotein (LDL) were the main contributors to serum binding for this series of compounds. The serum-drug binding data sorted the β-adrenoceptor blocking drugs into high and low binding categories. The protein mixture (AGP + HSA + HDL + LDL) resulted in dividing the β-blockers into the same high/low rankings. The protein mixture (AGP + HSA + HDL + LDL) was amenable to automation, did not autoaggregate, and had constant concentrations for the proteins.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190315
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    Separation of cis/trans conformers of human and salmon calcitonin by low temperature capillary electrophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 288-294 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Calcitonin ; Cis-trans conformers ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Conformer-specific recognition of peptides and proteins has often been proved with the aid of indirect methods. Here we provide an analytical approach for a direct investigation of separated isomers. Cis/trans conformers of the peptide hormones human (hCT) and salmon (sCT) calcitonin exhibit different migration properties in capillary zone electrophoresis at subambient temperatures. Calcitonin consists of 32 amino acids with two proline residues incorporated. It is the longest unstructured peptide for which a conformer separation by capillary electrophoresis has yet been achieved. Lowering the temperature yielded a splitting into two and three peaks for sCT and hCT, respectively, in acidic buffer. The peak ratios of 66:34 for sCT and 71:23 for hCT are in good agreement with the conformer distribution previously reported from nuclear magnetic resonance (NMR) studies. The addition of different organic modifiers (5-20% v/v) to the running buffer does not improve the separation. The observed merging of conformer peaks in buffer containing 20% v/v 2,2,2-trifluoroethanol (TFE) is attributed to structure formation.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190224
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 21
    Electronic Resource
    Electronic Resource
    Capillary affinophoresis of pea lectin with polyliganded affinophores: A model study of divalent-polyvalent interactions (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 397-402 
    Details
    ISSN: 0173-0835
    Keywords: Affinity electrophoresis ; Multivalency ; Affinity constant ; Capillary electrophoresis ; Lectin ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Affinophoresis is a type of affinity electrophoresis using an affinophore, a soluble ionic carrier bearing affinity ligand(s). It was reported previously that an affinophore, prepared by coupling multiple p-aminophenyl α-D-mannoside ligands to a part of the carboxyl groups of succinylated polylysine, specifically changed the mobility of pea lectin in agarose gel. The affinophoresis of this divalent lectin with the polyliganded affinophore was investigated by using capillary electrophoresis. Analysis of the mobility change of the lectin in the presence of differently modified affinophores showed that the affinity was larger for affinophores having higher ligand density. Analysis of the inhibition of the mobility change by a neutral ligand, with a known affinity constant for the lectin, allowed estimation of the contributions of monovalent and divalent interactions to the binding in the lectin-affinophore complex. The proportion of divalent complexes was greater for affinophores having higher ligand density. This approach to estimate the contribution of divalency in complex formation should be generally applicable to the analysis of divalent interactions with different techniques other than electrophoresis.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190306
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 22
    Electronic Resource
    Electronic Resource
    High sensitivity analysis of proteins and peptides by capillary electrophoresis-tandem mass spectrometry: Recent developments in technology and applications (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 885-892 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Mass spectrometry ; Protein ; Microfluidic device ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Analytical biochemistry, in particular the analysis of regulatory proteins that control biological systems and pathways, is dependent on methods of ever-increasing sensitivity. Capillary electrophoresis (CE) has long been recognized as an ultrasensitive analytical technique. In spite of the high sensitivity, CE has not penetrated protein discovery research as a standard analytical method. In this review article we summarize recent technical developments which have significantly enhanced CE as a tool for the analysis of trace amounts of proteins. Specifically, we review recent advances in the development and application of capillary electrophoresis-mass spectrometry (CE-MS) and on-line analyte concentration techniques, and introduce the emerging field of microfluidics as a front end to mass spectrometry (MS).
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190603
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 23
    Electronic Resource
    Electronic Resource
    Mixed-mode separation of polycyclic aromatic hydrocarbons (PAHs) in electrokinetic chromatography (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 723-730 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Polycyclic aromatic hydrocarbons ; Cyclodextrins ; Micellar ; Electrokinetic ; Sodium dioctyl sulfosuccinate ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: A mixed-mode separation technique has been developed and optimized for the separation of the 16 Environmental Protection Agency (EPA) priority polycyclic aromatic hydrocarbons (PAHs). The procedure utilized two different buffer additives as pseudo-stationary phases with different selectivities towards the analytes. Sodium dioctyl sulfosuccinate (DOSS) displayed selectivities for PAHs which were somewhat similar to the C18 phase in reversed-phase high performance liquid chromatography (HPLC). High acetonitrile content required for an effective separation prevented the formation of micelles as confirmed by fluorescence spectroscopy. Consequently, the separation could be attributed to the solvophobic association of the PAH molecules with hydrophobic chains of the DOSS surfactant. In another mode of separation, sulfobutylether-β-cyclodextrin (SB-β-CD) separated the 16 PAHs on the formation of inclusion complexes with the PAHs, and exhibited different selectivities for the PAHs compared to DOSS. SB-β-CD and DOSS were then combined in the running buffer to form a mixed pseudo-stationary phase for the separation of the 16 PAHs. Due to the different selectivities of SB-β-CD and DOSS for the PAHs, the separation of the 16 PAHs was appreciably improved compared to that using DOSS or SB-β-CD alone. All the 16 PAHs were baseline-resolved using an optimized running buffer containing 22.5 mM DOSS, 15 mM SB-β-CD, 15% acetonitrile and 5 mM hydroxypropyl-β-cyclodextrin in 6 mM borate at pH 9.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190521
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 24
    Electronic Resource
    Electronic Resource
    On the concept of “normalized buffering power/conductivity ratio” of isoelectric buffers for capillary zone electrophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 1674-1676 
    Details
    ISSN: 0173-0835
    Keywords: Isoelectric buffers ; Capillary electrophoresis ; Buffering power ; Conductivity ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The introduction of a new physico-chemical parameter is proposed: the “normalized buffering power/conductivity ratio”. It expresses the ratio of buffering power to conductivity (Rβ/λ), normalized by the electrolyte concentration, and gives an opportunity to calculate the properties of buffering ions typically used in capillary electrophoretic separations of biopolymers. This procedure of normalization is possible due to the fact that, in the concentration range practivally used, the relationship of Rβ/λ on concentration is close to linear.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191025
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 25
    Electronic Resource
    Electronic Resource
    Response patterns with indirect UV detection in capillary zone electrophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 1683-1690 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Indirect UV detection ; Response pattern ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Capillary zone electrophoresis with indirect UV-detection was used to separate mixtures containing both positively and negatively charged species. In order to understand the dependence of detector response patterns on the changes in compositions of the background electrolytes and the charge of marker ions (UV-absorbing ions), the separations were performed in two different systems. In a three-ion system (analyte ion, coion and counterion) a marker ion was the major ionic component of a buffer solution and in a two-coion or counterion system the marker ion was used as an additive. In the three-ion system the response profile of an analyte was in good agreement with the mathematical treatment based on the Kohlrausch regulation function. In the two-coion or counterion system the response patterns were more complicated; however, the experimental results agree well with data obtained from a computer simulation program. Peak directions of the analytes were not only determined by their relative charge to the marker ion, but were also associated with their relative mobilities to the buffer coion and the marker ion. The analytes with higher effective mobilities compared to the marker ion were detected as positive peaks and the ones with lower effectice mobilities as negative peaks. Similarly to the three-ion system, the detector response of an analyte was stronger by applying a marker coion compared to a counterion. An interesting result was obtained in the separation of a mixture of quaternary ammonium ions and sugars by using a cationic marker ion. The highest and most symmetrical peak was not a cation, but raffinose anion, which appeared most closely to the system peak. The observation suggests that the electromigration dispersion in its zone was eliminated by migrating close to the electroosmosis. A system peak with the mobility corresponding to the electroosmotic flow was obtained in both systems, and an additional system peak with a mobility close to that the marker ion was present in the systems using marker ions as additives.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191027
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 26
    Electronic Resource
    Electronic Resource
    The pH dependence of predictive models relating electrophoretic mobility to peptide chemico-physical properties in capillary zone electrophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2273-2277 
    Details
    ISSN: 0173-0835
    Keywords: Peptide ; Capillary electrophoresis ; Stokes radius ; Predictive models ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: We applied best fitting procedures to capillary electrophoresis (CE) mobility values, measured at varying acidic pH, of a set of 21 peptides with a molecular mass ranging from about 350 to 1850 Da. This method allowed the contemporary measurements of C-terminus and carboxylic group of the side-chain of aspartic and glutamic acid dissociation constants and of peptide Stokes radius at different protonation stages. Stokes radius was related to peptide molecular mass M at the power of a fractional coefficient, and best correlation was found at pH 2.25, the fractional coefficient being equal to 0.68. This value is close to that proposed by R. E. Offord (Nature 1966, 211, 591-593), who suggested a proportionality between the polymer Stokes radius and M2/3. The coefficient value decreases at higher pH, reaching a value of 0.58 at pH 4.25, corresponding to a mean peptide conformational transition towards more compact structures as a consequence of C-terminus dissociation. The measurement of the dissociation constants of each peptide allowed us to determine the percentage error on peptide charge predictions performed utilizing mean dissociation constants. Even for the charge, the best predictive performance is obtained at the most acidic edge of the range of the pH studied, mainly at pH 2.25. Conclusively, this study shows that the best performance of predictive models for peptide CE mobility is obtainable in the very acidic pH range (2.25-2.50) and in the absence of electroosmotic flow, and that a satisfactory predictive equation of peptide electrophoretic mobility (m2V-1S-1) is given by μ = 85.4(Z/M0.68)10-8.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191304
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 27
    Electronic Resource
    Electronic Resource
    Chemiluminescence detection in integrated post-separation reactors for microchip-based capillary electrophoresis and affinity electrophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2301-2307 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Microfluidics ; Immunoassay ; Microchip ; Chemiluminescence ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Chemiluminescence (CL) detection based on the horseradish peroxidase (HRP) catalyzed reaction of luminol with peroxide was investigated as a post-separation detection scheme for microchip-based capillary electrophoresis. An integrated injector, separator and post-separation reactor was fabricated on planar glass wafers. The fluorescein conjugate of HRP (HRP-F1) was used as a sample for optimization of the CL detector response. In devices etched 10 μm deep, with an aluminum mirror integrated onto the backside of the detection zone to enhance collection efficiency, the detection limit, estimated at 3 standard deviations (SD) above background noise, for 1 nL injected sample plugs was 35 nM in HRP-F1. In devices etched 40 μm deep, 8 nL plugs gave a detection limit of 7 nM. Separation and CL detection of the products of an immunological reaction of a F(ab')2 fragment of the HRP conjugate of goat anti-mouse immunoglobulin G (IgG) with mouse IgG was performed on-chip. A linear calibration curve was obtained for the decrease in peak height of the HRP conjugate (53 μg/mL) with increasing mouse IgG (0-60 μg/mL). When microperoxidase was used as an internal standard, the R2 value of a linear least-squares fit was 0.9867, and the relative errors in the slope and intercept were ± 5.8 and ± 1.3%, respectively.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191309
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 28
    Electronic Resource
    Electronic Resource
    Changes in outer membrane protein profiles of bacteria after meropenem-induced postantibiotic effect studied by capillary electrophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2324-2330 
    Details
    ISSN: 0173-0835
    Keywords: Outer membrane proteins ; Bacteria ; Postantibiotic effect ; Meropenem ; Capillary electrophoresis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Persistent inhibition of bacterial growth, called postantibiotic effect (PAE), after a short exposure to a new carbapenem, meropenem, was determined in different strains of the Enterobacteriaceae family. Capillary electrophoresis (CE), as well as sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) were used to study the outer membrane protein (OMP) profiles before and after meropenem treatment. CE proved to be suitable for the characterization of the OMP profiles of bacteria. Significant changes in the electrophoretic patterns were observed, showing the consequential effect of meropenem on bacteria.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191312
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 29
    Electronic Resource
    Electronic Resource
    Electrochemical detection in capillary electrophoresis with dual-parallel on-capillary electrodes (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2226-2232 
    Details
    ISSN: 0173-0835
    Keywords: Electrochemical detection ; Capillary electrophoresis ; Dual-parallel electrodes ; On-capillary electrodes ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: A new approach for dual electrode electrochemical detection in capillary electrophoresis (CEEC) is described. In this approach, two identical capillaries, each containing an on-capillary electrode incorporated permanently onto its tip, were paired together for simultaneous sample injection and detection. This procedure permitted dual-parallel detection to be performed without the need for painstaking alignment of the electrodes with respect to one another and to the capillary outlet as is required for the off-capillary microelectrode systems usually employed in CEEC. As a result, independent detection at two electrodes held at different potentials or at two electrodes of different composition or structure could be performed simply and with wide flexibility. Fabrication of on-capillary electrodes was carried out by sputter-coating the exit end of the capillaries with a thin layer of Au or Pt. Dual electrode system performance was demonstrated by separation and analysis of phenol and catechol samples. In addition, the detection system was coupled with glucose oxidase for the selective detection of glucose.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191230
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 30
    Electronic Resource
    Electronic Resource
    Differential diagnosis of gammopathies by capillary electrophoresis and immunosubtraction: Analysis of serum samples problematic by agarose gel electrophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2479-2484 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Serum proteins ; Immunosubtraction ; Immunofixation electrophoresis ; Monoclonal protein ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The capabilities of capillary electrophoresis (CE) for serum protein electrophoresis and immunotyping have been demonstrated. CE-based systems specifically designed for serum protein electrophoresis and immunotyping via immunosubtraction (IS) are now available and are being evaluated for efficiency, specificity and sensitivity by several groups. The use of CE for serum protein electrophoresis and immunotyping (IS) in the clinical laboratory compares well with agarose gel electrophoresis (AGE) and immunofixation (IF) for the detection and characterization of monoclonal proteins. In addition to routine use, this technology is useful for a subset of serum samples that are difficult to interpret with conventional technology. In this study, sera abnormalities difficult to detect/interpret by AGE-IF are subdivided into four categories: (i) patients with polyclonal increases in immunoglobulin, (ii) point of application artifacts, (iii) abnormalities in the beta region, and (iv) patients with free light chains. CE is superior to AGE for evaluating samples characterized by the above abnormalities. Sera containing monoclonal proteins within a polyclonal increase are easier to detect by CE as well as being easier to type by IS than by IF. Point-of-application artifacts, periodically observed with AGE, do not exist on CE since the point of detection is remote from the point of application. Enhanced resolution in the beta region allows for increased detection of monoclonal proteins migrating in this region. Some free light chains are undetected by CE as a result of no apparent abnormalities on the CE serum protein profile and, thus, still require IF for detection. CE detects more serum electrophoretic abnormalities than AGE in this clinically important group of patients with Bence Jones proteinemia.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191421
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 31
    Electronic Resource
    Electronic Resource
    Enhancement of sample loadings for the analysis of oligosaccharides isolated from Pseudomonas aeruginosa using transient isotachophoresis and capillary zone electrophoresis - electrospray - mass spectrometry (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2665-2676 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Electrospray ; Mass spectrometry ; Oligosaccharides ; Pathogenic bacteria ; Pseudomonas aeruginosa ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The analysis of underivatized core oligosaccharides arising from mild acid hydrolysis of lipopolysaccharides from Pseudomonas aeruginosa serotype O5 was achieved using a transient isotachophoretic preconcentration method coupled to capillary zone electrophoresis-electrospray-mass spectrometry (tCITP-CZE-ES-MS). The combination of a tCITP preconcentration step provided a 10- to 50-fold enhancement of sample loading and a corresponding improvement in sensitivity compared to the conventional zone electrophoresis format. Electrophoretic conditions, enabling the separation of these anionic analytes, were developed to determine possible sites of heterogeneity on either the core or the O-chain structures. The tCITP-CZE-ES-MS technique provided unparalleled resolution of the different core glycoforms and oligosaccharides obtained from the acid cleavage of the native endotoxins whether isolated following conventional gel permeation chromatography or obtained from direct hydrolysis of the bacterial isolates. These investigations also highlighted the highly phosphorylated nature of these complex cell membrane components, where the heptose residues of the core oligosaccharide can bear up to six phosphate groups# NRCC: 42370..
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191516
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 32
    Electronic Resource
    Electronic Resource
    A tabulated review of capillary electrophoresis of carbohydrates (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2539-2560 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Simple carbohydrates ; Glycoprotein glycans ; Glycopeptides ; Glycoforms ; Glycolipids ; Glycosaminoglycans ; Review ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: This review summarizes publications on capillary electrophoresis (CE) of carbohydrates, covering almost all hitherto published papers on this topic. It is designed to be a convenient tool for the literature search by providing a comprehensive table. Since CE analysis of carbohydrates is generally complicated due to the structural diversity of carbohydrate species, an attempt is made in this table to supply detailed information on the analyzed form (underivatized or derivatized, type of derivative) and analytical conditions (capillary size, state of the inner wall, composition of the electrophoretic solution, applied voltage, detection method, etc.), for each combination of carbohydrate species to be analyzed. In addition, a brief overview is presented to help in the literature search.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191503
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 33
    Electronic Resource
    Electronic Resource
    Faster capillary electrophoresis separation of wheat proteins through modifications to buffer composition and sample handling (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 3190-3198 
    Details
    ISSN: 0173-0835
    Keywords: Wheat ; Proteins ; Buffers ; Gliadins ; Capillary electrophoresis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Studies were conducted to produce faster, simpler, more rugged protocols for separating wheat proteins by high performance capillary electrophoresis (HPCE). Three areas were targeted for improvement: initial capillary equilibration procedures, buffer composition, and post-separation rinsing procedures. For the initial equilibration of capillaries, a brief rinse with a hydroxypropylmethylcellulose (HPMC) solution was the most critical factor for successful separation of wheat proteins. To reduce separation time and maintain resolution, β-alanine and glycine were each used in place of sodium phosphate as buffer ions. Two isoelectric buffers, aspartic acid and iminodiacetic acid (IDA) were also tested. Each of these four buffer systems generated substantially lower currents, and provided faster separations, than sodium phosphate-based buffers. Finally, post-separation rinsing procedures were re-examined with the goal of reducing the time necessary to rinse the capillary after each separation. A critical factor in achieving this goal was removal of albumins and globulins prior to separation. These proteins bind to the capillary wall and cause rising baselines and excessive peak tailing. Once these proteins were removed, capillaries could be rinsed with buffer for only 2 min between separations. Capillary equilibration procedures were shortened from 90 min to 30 min. Likewise, separation times were reduced by ∼ 40% (25 min to 15 min) by using glycine in place of sodium phosphate in the separation buffer. Finally, post-separation times were reduced by 80% (10 min to 2 min). Overall, these factors resulted in a reduction in total separation time of 50% (35 to 17 min) and maintained high resolution separations and good run-to-run repeatability.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191823
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 34
    Electronic Resource
    Electronic Resource
    Capillary electrophoretic analysis of ginseng polypeptide (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 1270-1274 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Lipolysis ; Magnesium ; Panax ginseng ; Peptide ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: A ginseng polypeptide (GPP) found in ginseng roots and its modified peptides were tested by capillary zone electrophoresis (CZE) under acidic as well as basic conditions. Modified peptides were synthesized for three purposes: (i) to analyze their functions in the first three acidic amino acid residues, (ii) to analyze their functions in three sequenced glycines, and (iii) to analyze the length of side chains in acidic amino acids. The roles of glycines, acidic amino acids and amino acid side chains in the binding of Mg2+ were studied at pH values less than 7.0. The migration times of GPP varied with the pH of various electrophoresis buffers, and electrophoresis patterns were significantly changed between pH 7.0-7.5. Based on the electrophoretic analysis, it was concluded that the binding mechanisms for Mg2+ or conformations of GPP changed between low pH and high pH.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190808
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 35
    Electronic Resource
    Electronic Resource
    A three-wavelength labeling approach for DNA sequencing using energy transfer primers and capillary electrophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 1403-1414 
    Details
    ISSN: 0173-0835
    Keywords: DNA sequencing ; Capillary electrophoresis ; Energy transfer primers ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Capillary electrophoresis DNA sequencing has been accomplished by using four different energy transfer primers and three fluorescence detection channels. Methods have also been developed to deconvolve the three-color data into the four base concentrations. The nonnegative least squares and model selection method resulted in the best accuracy. The three-color data were compared to sequencing data obtained using four detection channels and four energy transfer primers. The average accuracy rates obtained over three 500 base M13mp18 runs using three-color coding were 96% including 18 uncallable compressions and 99.6% if these compressions are excluded. The average accuracy rate obtained using four-color coding was 96.3% including 18 uncallable compressions and 99.9% if these compressions are excluded. Although it is unlikely that three-color schemes will replace four-color sequencing, these methods have exposed basic concepts that will be useful in the development of higher-order multiplex coding methods for DNA analysis.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190835
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 36
    Electronic Resource
    Electronic Resource
    Identifying human platelet glycoproteins IIb and IIIa by capillary electrophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 1468-1474 
    Details
    ISSN: 0173-0835
    Keywords: Glycoproteins ; Capillary electrophoresis ; Glanzmann's thrombasthenia ; Platelet membrane ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Glanzmann thrombasthenia (GT) is an inherited hemorrhagic defect due to a failure of the platelet membrane glycoprotein (GP) IIb-IIIa complex. Capillary electrophoresis (CE) analysis of solubilized platelet membranes from normal individuals showed the presence of two peaks with a migration time of 27 and 29 min, respectively. An excellent run-to-run and day-to-day reproducibility of the technique (〈 1% variation of the retention time) was documented. Using an automated Ferguson method, the apparent molecular masses were 100.0 kDa and 138.5 kDa, respectively. Immunoprecipitation with monoclonal antibodies anti-GP IIIa (B59.2.1) and anti-IIb (61.9.1.3) showed the two peaks as IIIa and IIb, respectively. Electropherograms of a GT young man showed the lack of both peaks. Less than 50% of each peak was present in his parents. Polyacrylamide gel electrophoresis (PAGE), immunoblotting, and flow cytometry analyses showed that GP IIb and IIIa were undetectable in the platelet membranes from the propositus, half of the normal amount being present in both parents. These findings indicate CE to be a rapid, sensitive and reliable tool to investigate patients with abnormalities of the GP IIb-IIIa complex.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190842
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 37
    Electronic Resource
    Electronic Resource
    Analysis of microdialysates from cancer patients by capillary electrophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2981-2985 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Interstitial drug kinetics ; Microdialysis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Microdialysis (MD) is an innovative clinical technique for measuring interstitial tissue pharmacokinetics and plasma-to-tissue transfer rates of drugs in humans. However, microdialysis requires the availability of specialized analytical techniques. Capillary electrophoresis (CE), which enables concentration measurements of small volume samples, theoretically constitutes an ideal analytical technique for measuring drug concentrations in microdialysates. In the present experiments, we aimed at assessing the potential utility and limitations of CE for analysis of microdialysates in a clinical situation. Microdialysates were obtained from primary breast cancer patients who received chemotherapy including 5-fluorouracil (5-FU; 600 mg/m2). Subsequently, 5-FU concentrations were measured in tumor - and subcutaneous adipose tissue - microdialysates by CE. By combining MD and CE, complete time versus concentrations profiles could be obtained for 5-FU in the interstitial tumor space and important clinical questions could be addressed. We conclude that the combination of MD and CE leads to important and previously inaccessible information about the drug distribution process in a clinical setting.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191630
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 38
    Electronic Resource
    Electronic Resource
    Viscosity-adjustable block copolymer for DNA separation by capillary electrophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 231-241 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; DNA separation ; Poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (EnPmEn) triblock copolymer ; Replaceable separation medium ; Electroosmotic flow ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The viscosity-adjustable property of F127 block copolymer PEO99PPO69PEO99, PEO and PPO being poly (ethylene oxide) and poly(propylene oxide), respectively, was found to be useful for the development of automated capillary electrophoresis (CE). The polymer solution can form a gel-like structure with sieving ability and can also serve as a dynamic coating material, thereby effectively suppressing the electroosmotic flow induced by the ionization of the silanol group on the quartz capillary inner wall. When applied to CE as a separation medium, F127 block copolymer can provide the advantages of high separation resolution, easy injection and replacement of the triblock copolymer solution and convenient capillary column treatment. High reproducibility of DNA electrophoretic migration time in CE by replenishing F127 solution in acid-washed capillary tubings can be achieved. The relative standard deviation of the DNA migration time is less than 2%. In the investigation of F127 concentration and temperature effects on the performance of DNA separation in CE, we have found that the DNA electrophoretic migration behavior in the F127 gel-like solution cannot be described by any one of the existing models.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190216
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 39
    Electronic Resource
    Electronic Resource
    Characterization of high molecular mass linear polyacrylamide powder prepared by emulsion polymerization as a replaceable polymer matrix for DNA sequencing by capillary electrophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 242-248 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Linear polyacrylamide ; Inverse emulsion polymerization ; DNA sequencing by capillary electrophoresis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: In a previous paper, a 2% w/w replaceable high molecular mass linear polyacrylamide solution (high molecular mass LPA) was used to achieve long readlengths for DNA sequencing by capillary electrophoresis (E. Carrilho et al. Anal. Chem. 1996, 68, 3305-3313). In that work, the polymer was prepared by polymerization in water at 6% w/w, followed by dilution to 2% w/w. In this study, an improved method for preparation of high molecular mass LPA was developed, based on inverse emulsion polymerization. With this polymerization procedure, the LPA results in a molecular mass of approximately 9 MDa with characteristics of a fine powder of high purity and practically unlimited shelf life. Using size exclusion chromatography (SEC) and viscosity measure ments to characterize the polymer, good batch-to-batch reproducibility was found. It was observed that the viscous polymer solutions made from these high molecular mass polymers require careful preparation and handling because the method of dissolution could affect the molecular mass distribution and the resultant separation of DNA components. Solution containing 2% w/w of LPA made by emulsion polymerization were simple to prepare resulting in excellent performance as a replaceable matrix for DNA sequencing by capillary electrophoresis. The viscosity of the polymer decreased exponentially when pressure was applied. allowing easy replacement from a capillary using a syringe. With a properly prepared matrix, a read-length on morethan 1000 bases in 80 min with an accuracy better than 97%, and better than 99% for the first 800 bases, could be achieved.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190217
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 40
    Electronic Resource
    Electronic Resource
    Separation of the enantiomers of ibuprofen and its major phase I metabolites in urine using capillary electrophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 455-460 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Ibuprofen ; Chiral separation ; Dextrin 10 ; Heptakis (2,3,6-tri-O-methyl)-β-cyclodextrin ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: A capillary electrophoresis method for determination of the enantiomers of ibuprofen and its major phase I metabolites: 2′-hydroxyibuprofen and 2′-carboxyibuprofen in urine samples have been developed. Cyclodextrins and linear dextrins have been investigated as chiral selectors. Simultaneous chiral separation of the enantiomers of ibuprofen, 2′-hydroxyibuprofen and 2′-carboxyibuprofen was obtained using a mixture of dextrin 10 and heptakis (2,3,6-tri-O-methyl)-β-cyclodextrin in a 2-[N-morpholino]ethanesulphonic acid buffer, pH 5.26. The electroosmotic flow was reversed using hexadimethrine bromide as a buffer additive. The method can be used for the determination of the free enantiomers of ibuprofen, 2′-hydroxyibuprofen and 2′-carboxyibuprofen as well as for the indirect determination of their glucuronic acid conjugates in urine samples.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190316
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 41
    Electronic Resource
    Electronic Resource
    High resolution capillary electrophoretic separation of oligonucleotides in low-viscosity, hydrophobically endcapped polyethylene oxide with cubic order (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 1699-1703 
    Details
    ISSN: 0173-0835
    Keywords: Oligonucleotides ; Capillary electrophoresis ; Self-associating polymer ; Physical gel ; End-capped polyethylene oxide ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: A triblock self-associating polymer with the structure n- dodecane-poly(ethylene oxide)-n-dodecane and a very low polydispersity has been used as a matrix to separate a sample of single-stranded oligonucleotides containing Pd(A)25-30 and Pd(A)40-60. Above a concentration of 4%, this associative polymer forms a micellar network with cubic order and a well-defined micellar spacing, in which the dodecane micellar cores are bridged by polyoxyethylene segments. This medium combines a low viscosity with excellent resolution of oligonucleotides. This work confirms that associative polymers are potentially powerful media for separation in capillary electrophoresis, and argues in favor of the use of monodisperse products presenting a high-order in the physical gel state.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191029
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 42
    Electronic Resource
    Electronic Resource
    On-line partial filling micellar electrokinetic capillary chromatography-electrospray ionization-mass spectrometry of corticosteroids (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 1711-1718 
    Details
    ISSN: 0173-0835
    Keywords: Partial filling technique ; Capillary electrophoresis ; On-line micellar electrokinetic capillary chromatography - electro-spray ionization - mass spectrometry ; Corticosteroids ; Mixed micelles ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The one-line combination of micellar electrokinetic chromatography (MECC) with electrospray ionization-mass spectrometry (ESI-MS) was investigated using some corticosteroids as model components. The on-line technique is difficult because the micelles in the electrolyte solution tend to soil the mass spectrometer and lower the sensitivity of the spectrometer. To prevent the micelles from reaching the mass spectrometer, several techniques have been developed among which is the partial filling (PF) technique. In this study the PF-MECC technique was investigated in an on-line MECC-ESI-MS study of mixtures of corticosteroids. Because the compounds are uncharged, partitioning or interaction with micelles is required to achieve separation. Surfactant solutions of sodium dodecyl sulfate (SDS), sodium cholate (SC), and SDS/SC mixtures were used as micellar phase. Good MECC separation was achieved after optimization of the surfactant concentrations and the length of the injected micellar plug. Both hydrodynamic and electrokinetic injections of the micellar solutions were tested. A basic ammonium acetate solution was used as the CE electrolyte solution. The ESI-MS analysis of the compounds was performed in the positive ionization mode, using an acidic sheath liquid. Because of the low MS intensities of the corticosteroids, the peaks were isolated during the MS runs. MS-MS and MS-MS-MS data on the corticosteroids were obtained by off-line injection of the compounds.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191031
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 43
    Electronic Resource
    Electronic Resource
    Use of a Hepta-tyr glycopeptide antibiotic as chiral selector in capillary electrophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 1742-1751 
    Details
    ISSN: 0173-0835
    Keywords: Antibiotics ; Chiral separations ; Enantiomers ; Drugs ; Herbicides ; Capillary electrophoresis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: A new glycopeptide antibiotic, MDL 63,246 (Hepta-tyr), of the teicoplanin family, has been evaluated in capillary electrophoresis for the resolution of chiral compounds of pharmaceutical and environmental interest. Electrophoretic separations were carried out in a polyacrylamide-coated capillary using the partial filling-counter current mode with aqueous-organic buffers in the pH range 4-6. Experimental parameters affecting resolution, such as antibiotic concentration, buffer pH, organic modifier type and capillary temperature, were studied. The Hepta-tyr antibiotic exhibited a high enantiorecognition capability towards the studied compounds at very low concentrations (1-2 mg/mL). The optimum experimental conditions were achieved by using a buffer at pH 5 containing acetonitrile at 25°C.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191036
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 44
    Electronic Resource
    Electronic Resource
    Use of scavenger beads to remove excess labeling reagents from capillary zone electrophoresis samples (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2129-2132 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Scavenger beads ; Fluorescence labeling ; Oligosaccharides ; Reagent removal ; Sample preparation ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: In many cases, samples for capillary zone electrophoresis (CZE) are derivatized with a chromophore or fluorophore to enhance their detectability. To ensure efficient labeling, a large excess of labeling agent is often used, which leads to the presence of a large peak for unreacted reagent. Here we report that excess reagent can be reacted with “scavenger beads” carrying an appropriate functional group to remove it from the sample solution. We present examples of removal of aminonaphthalene mono-, di-, and trisulfonic acid from mixtures in which they were used to label mono- or oligosaccharides by reductive amination. Aldehyde-containing scavenger beads were made by oxidizing Sephadex G-50 beads with sodium periodate. These were added to the labeling reaction mixtures after the reductive amination of the sugars was complete. Almost complete elimination of the peak from the labeling agent could be achieved.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191215
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 45
    Electronic Resource
    Electronic Resource
    Capillary electrophoresis of anions at high salt concentrations (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2133-2139 
    Details
    ISSN: 0173-0835
    Keywords: Sea water ; Capillary electrophoresis ; High salt concentrations ; Anion analysis ; Joule heating ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: It is commonly thought that even a moderately high ionic concentration in the background electrolyte (BGE) would leaad to Joule heating and serious peak distortion. However, we obtained very satisfactory separations of both inorganic and organic anions in electrolyte solutions as high as 5 M sodium chloride using direct photometric detection. Samples containing a 0.5 M concentration of a salt can be analyzed directly by making the BGE concentration of the same salt even higher to obtain electrostacking. The temperature in the center of the capillary was calculated to be 49°C when the current is at its maximum of 280 μA. The effect of various salts on electrophoretic and electroosmotic mobility is discussed. Several examples are given of capillary electrophoresis under high-salt conditions.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191216
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 46
    Electronic Resource
    Electronic Resource
    The effect of blob size and network dynamics on the size-based separation of polystyrenesulfonates by capillary electrophoresis in the presence of entangled polymer solutions (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2151-2162 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Polyelectrolytes ; Entangled polymers ; Network dynamics ; Polystyrenesulfonates ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: This work focuses on the separation of standard polystyrenesulfonates (PSS), with molecular masses (Mr) between 16 and 990 × 103 in capillaries filled with semidilute (entangled) linear hydrophilic polymers. Contrary to cross-linked chemical gels, which produce permanent networks, solutions of linear polymers lead to dynamic networks. The analytical performances and migration mechanisms are discussed on the basis of experiments performed in solutions of linear polyethyleneoxides and derivatized celluloses of various molecular masses. The influence of the mesh size and of the lifetime of the obstacles of the separating network has been investigated in detail. The mesh size is assimilated to the blob size of the separating polymer and is a decreasing function of its concentration. The lifetime of the obstacles of the network, identified with the reptation time of the polymer chain, characterizes its dynamics. This characteristic time increases with both the molecular weight of the separating polymer and its concentration. Its impact was first examined at fixed blob size. Then, the influence of the blob size was studied while keeping the reptation time of the network constant. By doing so, the existence of interactions between the solute and the separating polymer or between the solute and capillary wall can be more safely assessed. It appears that the reptation time of the mesh has a large influence on the electrophoretic mobility of the PSSs under a threshold value, which is of the order of magnitude of the time taken by the PSS to migrate on the blob size. Also shown are separations using networks made up with mixtures of polyethyleneoxides of the same nature and same mass concentration, but of very different molecular masses. This latter approach allows one to adapt the viscosity of the solution and the dynamics of the network, keeping the blob size constant.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191219
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 47
    Electronic Resource
    Electronic Resource
    Capillary electrophoresis and capillary electrophoresis - electrospray - mass spectroscopy for the analysis of heterocyclic amines (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2213-2219 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Electrospray mass spectroscopy ; Heterocyclic amines ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Fourteen heterocyclic amines (HAs) were analyzed by capillary electrophoresis (CE) on a polyvinyl alcohol (PVA)-coated capillary column. The optimized electrolyte is composed of 20 mM ammonium acetate, pH 3.0, and 20% methanol. Similar conditions were applied in electrospray - mass spectrometry (CE-ES-MS). The CE-ES-MS optimization procedure includes the position of the capillary in the stainless steel interface, the flow of the sheath liquid and its composition.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191228
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 48
    Electronic Resource
    Electronic Resource
    Capillary electrophoresis interfaced to inductively coupled plasma mass spectrometry for element selective detection in arsenic speciation (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2220-2225 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Interfacing ; ICP-MS ; Arsenic ; Speciation ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: A method is presented to separate and detect six arsenic species by capillary electrophoresis (CE) interfaced to inductively coupled plasma mass spectrometry (ICP-MS). CE was used as a highly resolving separation system, whereas ICP-MS served as an element selective detector providing low detection limits. The special mode of operation included sample stacking and a differentiation of separation and detection. This provided separation and detection of six As species, uncharged and anionic, to be monitored within a single run. Detection limits were calculated according to IUPAC recommendation at 15 μg As/L for As (III), dimethyl arsinic acid (DA), monomethyl arsonic acid (MA) and As (V), or 65 μg As/L for arsenobetaine (AsB) and arsenocholine (AsC). Investigations were focused on possibly occurring interferences, e.g., ArCl+ interference at the monoisotope 75As. Finally, real samples from biomedical field (urine) and environmental field (sewage sludge) were analyzed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191229
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 49
    Electronic Resource
    Electronic Resource
    Factors influencing the choice of buffer in background electrolytes for indirect detection of fast anions by capillary electrophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2257-2261 
    Details
    ISSN: 0173-0835
    Keywords: Background electrolyte ; Capillary electrophoresis ; Indirect detection ; Fast anions ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The suitability of relatively slow (low absolute value of mobility) coanionic buffers in background electrolytes (BGEs) for indirect photometric detection of anions by capillary electrophoresis was investigated. As a model system, 2-(cyclohexylamino)ethanesulfonic acid (CHES) was used to buffer the indirect detection electrolyte of sodium chromate. CHES (pKa 9.55) is a zwitterionic molecule carrying a net negative charge depending on the pH (effective charge -0.5 at pH = pKa). Within its useful pH buffering range CHES acted as a competing probe coanion. System peaks were induced which had deleterious effects on the detection sensitivity of slow to medium mobility anions. The mobility of the system peak was determined by the effective mobility of CHES, both of which increased with increasing pH. The peaks of analytes that migrated near or on the system peak were distorted and lost all quantitative properties. Analytes that migrated after the system peak either were not detected or reversed their responses. Analytes that migrated well before the system peak were unaffected. Consequently, the suitability of slow coanionic buffers is limited either to (i) fast anions or, (ii) a pH range much below the pKa, where the buffering capacity is not optimal.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191235
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 50
    Electronic Resource
    Electronic Resource
    Assay of trypsin activity by capillary isoelectric focusing with laser-induced fluorescence detection (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2296-2300 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Isoelectric focusing ; Laser-induced fluorescence ; Protease ; Enzyme assay ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Capillary isoelectric focusing is a highly effective method for the separation of proteins due to focusing as a function of their pI values in the separation process. This technique is also effective for certain types of peptides that focus well. Fluorescence labeling and subsequent detection by laser-induced fluorescence farther enhance the sensitivity of this technique. This paper demonstrates the utility of this technique in an enzyme assay. A synthetic nona peptide, H-Gly-Cys-His-Glu-Ala-Arg-Ala-Glu-Glu-OH, was labeled with an iodoacetyl derivative of Lissamine rhodamine B at the thiol group of the cysteine residue as a substrate for trypsin. Trypsin catalyzed the cleavage of the Arg-Ala bond of the labeled substrate, which focused at pH 4.8, and liberated a shortened, labeled product, H-Gly-*Cys-His-Glu-Ala-Arg-OH that focused at pH 6.9 (*indicates the label). The product peptide at 3-300 pM was determined with a relative standard deviation of 5.5% (n = 5) by fluorescence detection at 590 nm with excitation by a green line of He-Ne laser. Incubation of trypsin with the substrate for 10 min at 37°C allowed the determination of 50-250 pg of trypsin, with a relative standard deviation of 5.3% (n = 5).
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191308
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 51
    Electronic Resource
    Electronic Resource
    A survey of methodological challenges for glycosaminoglycan/proteoglycan analysis and structural characterization by capillary electrophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2561-2571 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Glycosaminoglycans ; Proteoglycans ; Review ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Proteoglycans participate and regulate several physiological processes via their glycosaminoglycan constituents. For a deeper understanding of how they interact with extracellular ligands as well as with cell bound effector molecules, the fine chemical structures of their glycosaminoglycan chains must be elucidated. Lately developed capillary electrophoretic techniques is a powerful analytical tool for the analysis of glycosaminoglycans, combining a high resolving power with sensitive detection. In this review we describe how depolymerized and intact glycosaminoglycans/proteoglycans can be characterized by capillary electrophoresis, relating these analyses to their possible biological significance. Conditions for running these separations and the detection systems for particular applications are also summarized.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191504
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 52
    Electronic Resource
    Electronic Resource
    Analysis of starch structure using fluorophore-assisted carbohydrate electrophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2603-2611 
    Details
    ISSN: 0173-0835
    Keywords: Starch ; Capillary electrophoresis ; Oligosaccharide ; Fluorophore-assisted carbohydrate electrophoresis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The analysis of the fine structure of starches is important to the investigation of linkages between starch structure and function and to the investigation of the properties and roles of starch biosynthetic, modifying and degradation enzymes. Fluorophore-assisted carbohydrate electrophoresis has recently been introduced as a method for the analysis of the oligosaccharide populations released by the enzymatic digestion of starches, which has advantages in resolution and sensitivity over previously used methods, and provides the capacity for the facile analysis of oligosaccharide populations on either a molar or mass basis. The use of fluorophore-assisted carbohydrate electrophoresis for the analysis of oligosaccharides is reviewed with particular reference to the choice of label, efficiency of labeling and separation techniques. Examples of separations using slab gel electrophoresis, DNA sequencer analysis and capillary electrophoresis are presented and we conclude that on the basis of resolution and reproducibility, capillary electrophoresis is the method of choice for the separation of oligosaccharides of degree of polymerization from 1 to 100. Examples of isoamylase-debranched starches and glycogens analyzed by capillary electrophoresis are presented. The capillary electrophoresis analysis of starch structure through the analysis of oligosaccharides released by the debranching of limit dextrins derived from starches and glycogens is introduced as a useful diagnostic of starch structure. The potential for future development of novel diagnostics for starch structure using fluorophore-assisted carbohydrate electrophoresis is discussed.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191507
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 53
    Electronic Resource
    Electronic Resource
    Characterization of DNA standards by capillary electrophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 1428-1435 
    Details
    ISSN: 0173-0835
    Keywords: DNA standards ; Capillary electrophoresis ; Ethidium bromide ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: We have used capillary electrophoresis to evaluate commercial DNA size standards and have found that it can provide an efficient assessment of size. However, the accuracy of the determination is adversely affected by anomalous migration times due to specific interactions of the DNA with the gel matrix as well as conformational differences in the DNA due to sequence heterogeneity. These anomalous migration times are strongly dependent on the choice of gel matrix. For example, the anomalous migration times that are observed in a 1 kilobase standard DNA ladder can be minimized using nongel hydroxyethylcellulose. In addition, the peak resolution can be increased and the anomalous migration can be reduced by the addition of the intercalating dye, ethidium bromide. However, in the case of the D1S80 allelic ladder, some of the DNA fragments possess nucleotide sequences which do not interact equivalently with the dye and produce irregular migration times. These measurements yield preliminary information useful in evaluating DNA size standards which may be used for a wide range of DNA diagnostic applications.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190837
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 54
    Electronic Resource
    Electronic Resource
    Multi-capillary optical waveguides for DNA sequencing (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 1415-1427 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; DNA sequencing ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Cylindrial capillaries can be used as optical elements in a waveguide, where refraction will confine an appropriately focused light beam to pass through the interiors of successive capillaries in a flat parallel array. Such a capillary waveguide allows efficient illumination of samples in multiple capillaries with relatively little laser power. Analytical expressions derived under paraxial and thin-lens approximations provide guidance in selecting the capillary sizes and the refractive indices that will produce the waveguiding effect, but accurate predictions require exact ray tracing. Small reflective losses as the light passes through the capillary surfaces cause cumulative intensity decreases, but the resulting lack of uniformity can be compensated to a considerable extent by illuminating the capillary array from both sides. A 12-capillary waveguide illuminated from both sides in air has a difference of less than 10% from the strongest to the weakest illumination. By increasing the refractive index of both the external medium and the contents of the capillaries, a 96-capillary waveguide for DNA sequencing could be produced that would also provide nearly uniform illumination. A 12-capillary, bi-directionally illuminated waveguide system for DNA sequencing has been constructed. The two focused laser beams are delivered by integrated fiber optic transmitters (IFOTs), and fluorescence is collected by a set of optical fibers whose spacing exactly matches that of the capillaries in the waveguide. The system is easy to align and provides sensitive detection of fluorescence with minimal cross-talk between channels.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190836
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 55
    Electronic Resource
    Electronic Resource
    The combined effect of acetonitrile and urea on the separation of polycyclic aromatic hydrocarbons using sodium dioctyl sulfosuccinate in electrokinetic chromatography (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 1461-1467 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Polycyclic aromatic hydrocarbons ; Micellar electrokinetic chromatography ; Sodium dioctyl sulfosuccinate ; Urea ; Acetonitrile ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Sodium dioctyl sulfosuccinate (DOSS) or sodium di2-ethylhexyl sulfosuccinate, a relatively nontoxic and negatively charged surfactant, was selected and optimized for the capillary electrophoretic separation of the 16 Environmental Protection Agency (EPA) priority polycyclic aromatic hydrocarbons (PAHs). This pseudostationary phase displayed selectivities for PAHs which were somewhat similar to the C18 phase in reversed-phase high performance liquid chromatography (HPLC). At high DOSS concentrations (〉 30 mM), the hydrophobic interaction between DOSS and PAHs was pronounced and led to stronger retention of the latter. Consequently, acetonitrile was added to the running buffer to facilitate the elution of hydrophobic PAHs. In the absence of micelles, the separation mechanism was attributed to the solvophobic association of the PAH molecules with hydrophobic chains of the DOSS surfactant and there was a linear correlation between log k (retention factor) and the double bond number of the PAH. However, separations performed in an optimized buffer containing both DOSS and acetonitrile were not able to provide satisfactory performance. The separation of the 16 PAHs was then appreciably improved by adding urea to the running buffer to widen the separation window. At a high sample loading with UV detection, except for benzo[a]pyrene, benzo[b]fluoranthene and benzo[k]fluoranthene, all other PAHs were practically baseline-resolved using an optimized running buffer containing 50 mM DOSS, 35% acetonitrile and 5 M urea in 8-10 mM borate, pH 9. Laser-induced fluorescence permitted a very low sample loading and under such a running condition, a baseline resolution was obtained for these three most difficult PAHs. The addition of urea at this level, however, exhibited a noticeable quenching effect on the PAH fluorescent signal.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190841
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 56
    Electronic Resource
    Electronic Resource
    Correlation of plasma protein separation patterns obtained by two-dimensional polyacrylamide gel electrophoresis and by capillary electrophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 1319-1324 
    Details
    ISSN: 0173-0835
    Keywords: Sodium dodecyl sulfate-polyacrylamide gel electrophoresis ; Human plasma proteins ; Two-dimensional polyacrylamide gel electrophoresis ; Myeloma proteins ; Isoelectric focusing ; Capillary electrophoresis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: We used three different electrophoretic techniques for the analysis of human plasma proteins: (i) two-dimensional polyacrylamide gel electrophoresis (2-D PAGE), with sodium dodecyl sulfate (SDS) used only in slab gel electrophoresis; (ii) capillary isoelectric focusing (CIEF) with no denaturants; (iii) linear polyacrylamide (LPA)-filled capillary electrophoresis with SDS (SDS-CE). With technique (i), data on isoelectric point and molecular size of plasma proteins can be obtained. Techniques (ii) and (iii) are suited to obtain quantitative information on proteins. The separation principle used in technique (ii) is closely related to that used in the first dimension of technique (i), and that used in technique (iii) related to that in the second dimension of technique (i). Therefore, we could successfully correlate protein separation patterns obtained by 2-D PAGE and those obtained by capillary electrophoresis. The advantages of correlating data obtained by various electrophoretic techniques in the course of constructing a comprehensive database on human plasma proteins are discussed.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190819
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 57
    Electronic Resource
    Electronic Resource
    Capillary electrophoresis for therapeutic drug monitoring (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2848-2855 
    Details
    ISSN: 0173-0835
    Keywords: Review ; Capillary electrophoresis ; Drug ; Monitoring ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Therapeutic drug monitoring is commonly used in both the ambulatory and hospital patient care settings. Routine measurement of concentrations of therapeutic agents in biological fluids is critical for certain drugs to maintain therapeutic benefit with minimizing drug-associated toxicities. Many analytical laboratory techniques are currently available to measure drug concentrations in biological samples. Recently there has been an increased interest in the use of capillary electrophoresis (CE) for measuring concentrations of therapeutic drugs in patient samples. However, while there are numerous reports of CE being used to measure drug concentrations in solution and pharmaceutical dosage forms, there are relatively few reports of the use of CE for measuring therapeutic agents in patient samples. The purpose of this paper is to provide an overview of methods currently used to measure therapeutic drugs in patient samples along with possible future trends for the use of CE in therapeutic drug monitoring.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191610
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 58
    Electronic Resource
    Electronic Resource
    A critical evaluation of the application of capillary electrophoresis to the detection and determination of 1,4-benzodiazepine tranquilizers in formulations and body materials (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2870-2882 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; 1,4-Benzodiazepines ; Formulations ; Body materials ; Review ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Studies of the capillary zone electrophoresis (CZE) and micellar electrokinetic capillary chromatography (MEKC) behaviour of 1,4-benzodiazepines have seen application in subject areas such as the development of pharmaceuticals, therapeutic drug monitoring and forensic toxicology. In the development of pharmaceuticals, pKa determinations by CZE can be used in preclinical studies whereas analytical data on the detection and determination of 1,4-benzodiazepines is of value primarily in raw material/formulation assay and in the analysis of body fluids in clinical studies. The capillary electrophoresis (CE) techniques, which generally have inferior limits of detection (LOD) to rival techniques such as gas chromatography (GC) and high-performance liquid chromatography (HPLC), are particularly applicable in forensic toxicology where reasonably high concentrations of these drugs can be encountered. It is anticipated that, with the interfacing of CZE and capillary electrochromatography (CEC) with mass spectrometry (MS) techniques, the excellent selectivity of CZE and particularly CEC will be effectively combined with the sensitivity of MS and the identification capabilities of tandem mass spectrometry (MS/MS) and MS hyphenated (MSn) techniques.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191613
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 59
    Electronic Resource
    Electronic Resource
    Two examples of rapid and simple drug analysis in pharmaceutical formulations using capillary electrophoresis: Naphazoline, dexamethasone and benzalkonium in nose drops and nystatin in an oily suspension (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2907-2911 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Naphazoline ; Dexamethasone ; Benzalkonium ; Nystatin ; Nonaqueous capillary electrophoresis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Capillary electrophoresis is a versatile tool in pharmaceutical analysis. In the course of a revision of the “Standardrezepturen”, a German formula of standard dispensings for preparation in pharmacies, this technique has been applied to drug analysis in pharmaceutical formulations. The present paper deals with two different examples. First, naphazoline, dexamethasone and the preservative benzalkonium are quantified in nose drops without any sample preparation. Second, the antifungal antibiotic nystatin is quantified using nonaqueous capillary electrophoresis in methanol after sample preparation from an oily suspension.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191618
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 60
    Electronic Resource
    Electronic Resource
    Determination of atropine in biological fluids by micellar electrokinetic capillary chromatography in the presence of strychnine and tetracaine (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 3003-3007 
    Details
    ISSN: 0173-0835
    Keywords: Atropine ; Strychnine ; Tetracaine ; Capillary electrophoresis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The identification and quantitation of atropine, in whole blood and gastric contents in the presence of strychnine and tetracaine is described. This method uses liquid-liquid extraction and micellar electrokinetic chromatography (MECC). Separations are made using a 50 cm long capillary and a borate/phosphate buffer at pH 9.2 with 50 mM sodium dodecyl sulfate (SDS). Linearity was established for the three compounds between 1.0 and 100 μ/mL, using scopolamine as internal standard. The limit of detection for atropine was estimated at 0.06 μ/mL and the limit of quantitation at 0.2 μg/mL. The run time is less than 30 min. Alternate parameters are proposed to reduce the run time to under 10 min. The method was applied to a forensic post-mortem case.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191634
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 61
    Electronic Resource
    Electronic Resource
    Screening for urinary amphetamine and analogs by capillary electrophoretic immunoassays and confirmation by capillary electrophoresis with on-column multiwave-length absorbance detection (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2956-2966 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Amphetamines ; Ephedrines ; Immunoassay ; Confirmation testing ; Multiwavelength detection ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: This paper characterizes competitive binding, electrokinetic capillary-based immunoassays for screening of urinary amphetamine (A) and analogs using reagents which were commercialized for a fluorescence polarization immunoassay (FPIA). After incubation of 25 μL urine with the reactants, a small aliquot of the mixture is applied onto a fused-silica capillary and unbound fluorescein-labeled tracer compounds are monitored by capillary electrophoresis with on-column laser-induced fluorescence detection. Configurations in presence and absence of micelles were investigated and found to be capable of recognizing urinary D-(+)-amphetamine at concentrations 〉 about 80 ng/mL. Similar responses were obtained for racemic methamphetamine (MA) and 3,4-methylenedioxymethamphetamine (MDMA). The electrokinetic immunoassay data suggest that the FPIA reagent kit includes two immunoassay systems (two antibodies and two tracer molecules), one that recognizes MA and MDMA, and one that is geared towards monitoring of A. For confirmation analysis of urinary amphetamines and ephedrines, capillary electrophoresis in a pH 9.2 buffer and multiwavelength UV detection was employed. The suitability of the electrokinetic methods for screening and confirmation is demonstrated via analysis of patient and external quality control urines.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191627
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 62
    Electronic Resource
    Electronic Resource
    Analysis of recombinant cytokines in human body fluids by immunoaffinity capillary electrophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2991-2996 
    Details
    ISSN: 0173-0835
    Keywords: Immunoaffinity ; Capillary electrophoresis ; Cytokines ; Body fluids ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: An immunoaffinity capillary electrophoresis (ICE) system for rapidly quantifying recombinant cytokines in human body fluids has been developed. Cytokines within biological fluids were labeled with a red light emitting fluorochrome and injected into the capillary. Selected cytokines were captured by immobilized antibodies on the internal surface of the capillary, and held while unbound materials were purged. The cytokines were then eluted electrophoretically in acidic buffer. Individual cytokine peaks were detected by on-line laser-induced fluorescence detection coupled to a computerized fiber-optic spectrometer, and analyzed by integration of the eluted peaks. The comparison of the results of ICE to routine assays used for these cytokines demonstrates that ICE provides a fast and accurate procedure for defining these cytokines in complex biological samples. Immunoaffinity separations can be used for any material to which a specific antibody can be raised, making this procedure applicable to a wide range of molecules of biomedical interest.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191632
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 63
    Electronic Resource
    Electronic Resource
    Analysis of isoquinoline alkaloids in medicinal plants by capillary electrophoresis - mass spectrometry (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 3026-3032 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Mass spectrometry ; Electrospray ionization ; Isoquinoline alkaloids ; Medicinal plants ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The technique of capillary electrophoresis - mass spectrometry (CE-MS) was applied for determination of isoquinoline alkaloids in crude methanolic extracts of medicinal plants. For the CE separations ammonium formate buffer solutions (70 or 100 mM, pH 3.0 or 4.0) containing 10% methanol or 20-60% acetonitrile as additives were used. The applied voltage was 25 kV, the thermostating temperature was kept constant at 25°C. Coupling with the mass spectrometer was performed via an atmospherical pressure ionization (API) interface and the electrospray ionization technique (ESI). As sheath liquid 5 mM formic acid in acetonitrile at a flow rate of 3 μL/min was used. The spray voltage was 4.5 kV and the temperature of the heated capillary was chosen to be 200°C. Detection in the positive ionization mode resulted in mass spectra showing either the molecular ions [M]+ or the protonated molecular ions [M+H]+. The presented method allows detection and identification of isoquinoline alkaloids in crude methanolic extracts of medicinal plants as Eschscholzia californica CHAM. (Papaveraceae), Hydrastis canadensis L. (Ranunculaceae), Berberis vulgaris L. (Berberidaceae), Jateorhiza palmata (LAM.) MIERS (Menispermaceae) and Chelidonium majus L. (Papaveraceae).
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191639
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 64
    Electronic Resource
    Electronic Resource
    Capillary electrophoretic determination of trace metals in hair samples and its comparison with high performance liquid chromatography and atomic absorption spectrometry techniques (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 11-18 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Metals ; Hair ; High performance liquid chromatography ; Atomic absorption spectrometry ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Capillary electrophoresis (CE) is compared with high performance liquid chromatography (HPLC) and atomic absorption spectrometry (AA) for the determination of trace concentrations of selected metals in human hair. CE and HPLC methods are based upon the chelation of the metals with 2-(5′-bromo 2′-pyridylazo)-5-diethylamino phenol (5-Br-PADAP) followed by ultraviolet-visible (UV-Vis) detection. Large volume sample stacking (LVSS)-CE using injection times of up to 300 s is applied to the simultaneous determination of Co and Zn providing lower limits of detection (LODs) of 4.2 × 10-8 mol dm-3 and 6.0 × 10-8 mol dm-3, respectively, than can be achieved by conventional CE. The LVSS procedure could not be applied to hair samples due to a higher run current existing when the sample is introduced into the capillary. Conventional CE with cetyltrimethylammonium bromide (CTAB) present in the run buffer to retain the ligand in solution is used for the determination of metal concentrations in hair samples. Only Zn could be determined in this way as it exists at relatively high levels in hair. Co, Ni and Hg could be detected when spiked hair samples were analysed with estimated LODs of 5.0 × 10-7 mol dm-3, 1.0 × 10-6 dm-3 and 3.0 × 10-5 mol dm-3, respectively. HPLC was successfully used to determine Co and Cu in hair samples, with levels of 57.6 ppb and 17.31 ppm being found, respectively, and corresponded closely to results produced by AA. Fe also gave a signal together with unidentified coeluting species. In a separate HPLC study the determination of Ni and Hg as their complexes with hydrogen peroxide and 5-Br-PADAP was also investigated and LODs of 2.0 × 10-6 mol dm-3 and 5.0 × 10-6 mol dm-3, respectively, were achieved. AA was used as a reference method to determine levels of Co, Cu, Fe, Pb and Zn in hair and the results produced were in order of magnitude agreement with accepted literature values.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190105
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 65
    Electronic Resource
    Electronic Resource
    Simultaneous chiral separation of 3,4-methylenedioxymethamphetamine (MDMA), 3-4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxyethylamphetamine (MDE), ephedrine, amphetamine and methamphetamine by capillary electrophoresis in uncoated and coated capillaries with native β-cyclodextrin as the chiral selector: Preliminary application to the analysis of urine and hair (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 42-50 
    Details
    ISSN: 0173-0835
    Keywords: Amphetamine ; Methamphetamine ; Chiral analysis ; Capillary electrophoresis ; Urine ; Hair ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The importance of the chiral analysis of amphetamine-related substances in both clandestine preparations and biological samples is widely recognized. For this purpose, capillary electrophoresis was successfully applied by several authors, but only few reports concerned ring-substituted amphetamines, which represent the main components of “ecstasy”, a widely abused “recreational” substance. In the present work, the simultaneous chiral analysis of ephedrine, amphetamine, methamphetamine, 3,4-methylenedioxymethamphetamine (MDMA), 3-4-methylenedioxyamphetamine (MDA) and 3,4-methalenedioxyethylamphetamine (MDE) is reported, by using capillary electrophoresis with native β-cyclodextrin (15 mM) as the chiral selector. After preliminary tests at different pH values (phosphate buffer 100 mM, pH 2.5-9.0) and with bare or coated fused-silica capillaries, the optimized conditions were: pH 2.5 phosphate, uncoated capillary (45 cm × 50 μm inner diameter), potential 10 kV. Detection was either by fixed wavelength (200 nm) or multiwavelength (190-400 nm) UV absorbance. Under these conditions, good resolution was obtained for all the analytes, with excellent chiral selectivity and efficiency. The sensitivity for the individual enantiomers was better than 0.2 μg/mL, analytical precision was characterized by relative standard deviation values 〈 0.8% (≤ 0.15% with internal standardization) for migration times intra-day and 〈 2.0% (≤ 0.54% with internal standardization) day-to-day; linearity, in the range 0.156-40 μg/mL, and accuracy were also satisfactory. After a simple liquid-liquid extraction, urine samples could be analyzed with a sensitivity well below the recommended NIDA cut-off of 500 ng/mL. For hair samples, it was necessary to increase the sensitivity by applying a field-amplified sample stacking procedure, which allowed the chiral determination of MDA, MDMA and MDE at concentrations occurring in real samples from ecstasy users, with the possibility of recording UV spectra of the peaks.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190109
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 66
    Electronic Resource
    Electronic Resource
    Screening for urinary methadone by capillary electrophoretic immunoassays and confirmation by capillary electrophoresis-mass spectrometry (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 57-65 
    Details
    ISSN: 0173-0835
    Keywords: Methadone ; Immunoassay ; Capillary electrophoresis ; Mass spectrometry ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: This paper characterizes competitive binding, electrokinetic capillary-based immunoassays for urinary methadone using reagents which were commercialized for a fluorescence polarization immunoassay. After incubation of 25 μL urine with the reactants, a small aliquot of the mixture is applied onto a fused-silica capillary and the unbound fluorescein-labeled methadone tracer is monitored by capillary electrophoresis with on-column laser-induced fluorescence detection. Configurations in presence and absence of micelles were investigated, found to be capable of recognizing urinary methadone concentrations ≥ 10 ng/mL, and shown to be suitable for rapid methadone screening of patient urines. Based upon shorter run times and a much better separation of free tracer and antibody-tracer complex, conditions without micelles are preferred. For confirmation analysis of urinary methadone and its major metabolite, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), capillary electrophoresis in a pH 4.6 ammonium acetate-acetic acid buffer was interphased to an atmospheric pressure ionization triple quadrupole mass spectrometry system. Using positive ion electrospray ionization and the tandem mass spectrometry mode with collision-induced dissociation in the collision cell, fragmentation of the two substances was determined. For confirmation via direct urine injection or application of a urinary extract, in-source fragmentation was employed and the first quadrupole was operated in the selected ion monitoring mode by switching between the masses of relevant precursor/product ion sets for methadone (m/z = 310, 265) and EDDP (m/z = 278, 249, 234). This capillary electrophoresis - mass spectrometry approach is shown to permit the confirmation of methadone and EDDP in patient urines that tested positive for methadone using electrokinetic capillary-based immunoassays, a fluorescence polarization immunoassay, and capillary electrophoresis with UV absorption detection.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190111
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 67
    Electronic Resource
    Electronic Resource
    Sequencing using capillary electrophoresis of short tandem repeat alleles separated and purified by high performance liquid chromatography (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 108-118 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; High performance liquid chromatography ; DNA sequencing ; Ion-pairing reverse-phase liquid chromatography ; Peak capture ; Short tandem repeat ; Fragment length polymorphism ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Polymerase chain reaction (PCR) amplified alleles need to be isolated and purified before carrying out additional analysis to confirm sequence, number of repeats and microvariants within a short tandem repeat (STR) locus. Also, PCR amplification of tetranucleotide repeat loci, used in DNA typing assays, often result in heteroduplex formation, adding to the complexity of analysis. Sequencing reactions require single specific target DNA for reliable sequencing analysis. Alkylated poly(styrene-divinylbenzene) columns at elevated temperature and gradient elution conditions increase the efficiency of separation to allow for the purification of PCR products. Using the separation technique of ion-paring reverse-phase (IPRP) high performance liquid chromatography (HPLC), molecular biologists can separate and purify DNA fragments without alteration to the double-stranded DNA sequencing properties. In this study, the IP-RP chromatography technique has been demonstrated by separation of alleles of the short tandem repeat loci of TH01, vWA31, F13A01 and FES/FPS. Alleles differing in size range of 12 to 4 base pairs were separated by IPRP/HPLC and individual alleles were peak-captured, then cycle-sequenced. These HPLC fractions required no additional steps prior to cycle sequencing. Capillary electrophoresis (CE) was used to sequence the alleles. Furthermore, CE offers advantages over traditional slab methods via automation and higher applied voltages. Interestingly, unlike traditional gel electrophoresis, samples were introduced into the sieving matrix by electrokinetic injection, which allows for multiple injections from a single sample, a key feature for method development. Applied voltage was 320 V per centimeter using a nonderivatized fused silica capillary with an interior diameter of 50 μm and a total length of 47 centimeters. The total analysis time including capillary filling and pre-electrophoresis was less than 30 min for a 220-bp fragment. A sequencing rate of 530 bp/h was achieved using these conditions. By combining the techniques of HPLC separation and CE sequencing, the results confirmed the sequence and number of nucleotide repeats for each STR loci. An average sequencing efficiency of 97% was achieved. Additionally, this method defined the absence of a 9.3 microvariant for a TH01 heterozygous individual previously typed as a 9,9.3/10 using slab gel electrophoresis. The techniques described can be applied to other DNA purification and isolation problems.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190119
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 68
    Electronic Resource
    Electronic Resource
    Detection of p53 point mutations by single strand conformation polymorphism: Analysis by capillary electrophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 172-179 
    Details
    ISSN: 0173-0835
    Keywords: DNA p53 mutation detection ; Capillary electrophoresis ; Slab gel electrophoresis ; Single strand conformation polymorphism ; Temperature dependence ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: We have analyzed five p53 single point mutations by single strand conformation polymorphism using capillary electrohoresis (CE-SSCP) and have compared these measurements to measurements obtained by slab gel electrophoresis (SG-SSCP). PCR primers were used for amplification of specific exons for mutation detection. 5′ Primers were labeled with FAM (5-carboxyfluorescein) and 3′ primers were labeled with JOE (2′,7′-dimethoxy-4′,5′-dichloro-6-carboxyfluorescein). CE-SSCP was performed using the Perkin Elmer ABI PRISM™ 310 Genetic Analyzer with GeneScan™ Software and the Beckman P/ACE™ 5510 CE equipped for laser-induced fluorescence detection. Although the shifts in migration times for the p53 mutations relative to the corresponding wild-type strands could be successfully detected by either SG or CE analysis, the individual electrophoresis run times were about tenfold faster and more automated with capillary electrophoresis. The CE-SSCP measurements were performed at temperatures ranging from 10 to 60°C on a prototype instrument. For mutations measured at ambient temperature (25°C), characteristic shift in direction and magnitude were observed in the migration times to both strands of all mutations relative to the wild type. This demonstrated the ability of CE at ambient temperature to resolve these mutations. However, the magnitute and direction of shifts in migration time varied with temperature in a discrete pattern for each mutation and resulted in a temperature-specific profile for each mutation. This demonstrated that extended temperature control will be an important advantage in resolving single point mutations by CE-SSCP. In addition, by using CE, discrete intra-strand isoforms could be easily observed at different temperatures. The combination of mutation-specific temperature profiling and analysis of isoforms by CE-SSCP should be of help to the diagnostic community in the detection of genetic mutations.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190207
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 69
    Electronic Resource
    Electronic Resource
    Forensic validation of the short tandem repeat HUMACTBP2 using capillary electrophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 256-261 
    Details
    ISSN: 0173-0835
    Keywords: Short tandem repeat ; HUMACTBP2 ; Capillary electrophoresis ; Forensic validation ; Population data ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Experiments were performed to evaluate the forensic identification of the short tandem repeat (STR) HUMACTBP2 (human beta-actin-related pseudogene) using automated fluorescence-based capillary electrophoresis. The HUMACTBP2 is a complex tetranucleotide STR locus with more than 32 alleles in the range of 202-323 bp. The reproducibility of genetic typing using a fluorescent labeled allelic ladder was determined by comparison of the calculated fragment size after consecutive (within-day) and nonconsecutive (day to day) injection. The maximum variation in size (window) observed for any allele was 0.23 bp for the within-day and 0.8 bp for the day-to-day precision. Furthermore, it is possible to achieve a 1 bp resolution, the precision of the reproducibility assays being about 99.95%. Sixty blood samples and twenty stains were typed with both automated fluorescent sequencer ABI 373A and ABI 310. Identical genotypes were obtained with both techniques and the ABI 310 seemed to be more sensitive than the ABI 373A. A population sample of 197 unrelated individuals from southwest Switzerland was analyzed and the genotype frequencies observed were similar to those reported by others. Thirty-one alleles and 126 genotypes were found. The observed heterozygosity was 0.934. Mixtures from two different blood samples varying in their ratio were typed and the minor fraction was detectable to about 1:10. The practical usefulness of the HUMACTBP2 is illustrated by analyzing casework samples. This validation study proves the usefulness of the HUMACTBP2 locus in forensics and the detection efficiency using fluorescent capillary electrophoresis.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190219
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 70
    Electronic Resource
    Electronic Resource
    Stereoselective interaction of drug enantiomers with human serum transferrin in capillary zone electrophoresis (II) (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 282-287 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Chiral separation ; Transferrin ; Drugs ; Surface binding site ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Further studies on chiral resolution of drugs with different chemical structures by capillary zone electrophoresis using iron-free human serum transferrin are described. The substances passed a highly concentrated pseudo-stationary protein zone applied in a coated capillary and the possible chiral separation of the optical isomers was followed. Eighteen drugs with different structures were screened, and the enantiomers of clofedanol, buphenine, acebutolol and chlorphenamine were resolved. Several, but not all drugs, showed longer migration times while passing the protein zone, indicating an interaction with transferrin, although chiral resolution was not observed in all cases. The observations provided further information about the properties of the surface interaction sites of transferrin.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190223
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 71
    Electronic Resource
    Electronic Resource
    Affinity capillary electrophoresis employing immobilized glycosaminoglycan to resolve heparin-binding peptides (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 437-441 
    Details
    ISSN: 0173-0835
    Keywords: Glycosaminoglycan ; Affinity ; Capillary electrophoresis ; Heparin-binding peptides ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: A new capillary electrophoresis technique has been developed for the affinity resolution of synthetic heparin-binding peptides using an immobilized glycosaminoglycan. Heparin and heparan sulfate were immobilized onto fused silica capillaries using biotin-neutravidin conjugation. These capillaries exhibited markedly reduced electroosmotic flow and were able to distinguish peptides based on the heparin binding domain of acidic fibroblast growth factor (residues 125-144, GLKKNGSCKRGPRTHYGQKA) that differed only in the stereochemistry of the proline amino acid residue. The peptide based on the native sequence was retarded compared to the peptide having unnatural stereochemistry, consistent with its stronger interaction for immobilized glycosaminoglycan. Improved resolution is also obtained for additional arginine and lysine containing heparin-binding peptides.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190313
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 72
    Electronic Resource
    Electronic Resource
    Enantiomeric separation of methadone by cyclodextrinbased capillary and recycling isotachophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 1081-1090 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Isotachophoresis ; Cyclodextrin ; Methadone ; Circular dichroism ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The separation of methadone enantiomers by cationic capillary isotachophoresis (CITP) and recycling isotachophoresis (RITP) having (2-hydroxypropyl)-β-cyclodextrin (OHP-β-CD) as chiral selector in the leading electrolyte is described. Sodium acetate/acetic acid (pH between 4 and 5) served as leading electrolyte (catholyte) and acetic acid as terminator (anolyte). Complete separation of the enantiomers was obtained by CITP in a 50 μm internal diameter (ID) fused-silica capillary and in a 500 μm ID Teflon capillary. In the first approach, enantiomeric separation could be monitored via UV absorbance detection at low wavelength. With the second instrumental setup, an additional conductivity sensor permitted the visualization of the enantiomeric separation and the characterization of the buffer system employed. A 10 mM sodium acetate/acetic acid leading buffer of pH 4.3, containing 5 mM OHP-β-CD, was found to provide best enantiomeric separation and was thus chosen for RITP. With RITP processing of a few mg of racemic methadone, partial separation of methadone enantiomers was obtained. R-(-)-methadone and S-(+)-methadone were found to be significantly (up to about 80%) enriched at the front and back side, respectively, of the isotachophoretic zone. The enantiomeric composition of methadone in the collected fractions was assessed by chiral capillary zone electrophoresis (CZE) and circular dichroism spectroscopy. CZE was found to represent a simple and efficient method for the determination of the enantiomeric excess, whereas the latter technology was noted to be the superior approach for properly characterizing fractions that contain similar amounts of the two enantiomers. Furthermore, chiral RITP and analysis of the collected fractions by circular dichroism spectroscopy is shown to be potentially useful for identification of single enantiomers in absence of pure chiral standards.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190706
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 73
    Electronic Resource
    Electronic Resource
    Surface modification based on Si-O and Si-C sublayers and a series of N-substituted acrylamide top-layers for capillary electrophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 1677-1682 
    Details
    ISSN: 0173-0835
    Keywords: Coating ; Electroosmosis ; Silica ; Capillary electrophoresis ; N-substituted acrylamide ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Two approaches were used to prepare a series of surface-modified capillaries. In the first, a sublayer was formed by coupling γ-methacryloxypropyltrimeth-oxysilane to the surface silanol groups forming an SI-O bond; a top layer was then formed by polymerizing acrylamide in the capillary, which reacted with the sublayer. In the second approach, a sublayer was formed by silanol chlorination, followed by Grignard coupling of vinylmagnesium bromide to form an Si-C bond at the surface; a top layer was formed by polymerizing either acrylamide (AA), dimethylacrylamide (DMA), N-acryloylaminoethoxyethanol (AAEE), or N-acryloylaminopropanol (AAP) onto the sublayer. The Si-C-poly(AA) capillaries were more stable and produced an approximately 10-fold lower electroosmotic flow compared to the Si-O-poly(AA) capillaries. The Si-C sublayer was used to compare the performance of all four top layers. Electroosmotic flow decreased in the order: Si-O-poly(AA), Si-C-poly(AA), Si-C-poly(AAEE), Si-C-poly(DMA), and Si-C-poly(AAP). Si-C-poly(AA) showed evidence of irreversible degradation at pH 9 already after 40-50 runs. Si-C-polyAAP-coated capillaries demonstrated superior efficiency and migration time reproducibility for a number of alkaline proteins and for fluorescently labeled ovalbumin. Excellent performance was maintained, in the case of poly(AAP), for a least 300 runs (of 30 min duration) at pH 9.0.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191026
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 74
    Electronic Resource
    Electronic Resource
    Predictive model for capillary electrophoretic peptide mobility in 2,2,2-trifluoroethanol-water solution (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 1728-1732 
    Details
    ISSN: 0173-0835
    Keywords: Peptide ; Capillary electrophoresis ; Stokes radius ; Predictive models ; 2,2,2-Trifluoroethanol ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Using capillary electrophoresis (CE) on a set of 21 peptides with a molecular mass ranging from about 350 to 1850 Da, the Stokes radii at different protonation stages and the acidic dissociation constants in water and in a 2,2,2-trifluoroethanol (TFE) water mixture (30% v/v) were determined. These results permitted us to establish separately the reliability of semiempirical models utilized for the prediction of peptide size and charge at different acidic pHapp (pHapp range: 2.00-4.25). The data obtained on size and charge were utilized in order to provide suitable mobility predictions on the basis of the charge-to-size ratio. The best predictive conditions for size and charge were found at the most acidic range of pHapp studied (2.00-2.25), either in water or a TFE-water mixture, and reliable predictive equations for peptide mobility were established at this pHapp.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191033
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 75
    Electronic Resource
    Electronic Resource
    Human globin chain separation by capillary electrophoresis in acidic isoelectric buffers (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 1733-1737 
    Details
    ISSN: 0173-0835
    Keywords: Globin chains ; Isoelectric buffers ; Capillary electrophoresis ; Thalassemia ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: A simple and reliable method, utilizing capillary electrophoresis in uncoated capillaries in acidic isoelectric buffers, is reported for screening for thalassemia and other defects on the synthesis of human globin chains. A solution of 50 mM iminodiacetic acid (pi2.23), containing 7 M urea and 0.5% hydroxyethyl-cellulose (apparent pH 3.2) is used as background electrolyte for fast separation of heme-free, denatured globin (α, β and γ) chains. Due to the low conductivity of such a buffer, high voltage gradients (600 V/cm) can be applied, thus reducing the separation time to only a few minutes. It is additionally shown that inclusion of 2% surfactant (Tween 20) in the background electrolyte induces the splitting of the γ chains into two zones, called Aγ and Gγ, which represent the products of two genes coding for Ala or Gly as residue 136 of the chain.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191034
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 76
    Electronic Resource
    Electronic Resource
    Capillary electrophoresis chiral separations of basic compounds using cationic cyclodextrin (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2095-2100 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Chiral separations ; Cationic cyclodextrin ; Basic racemates ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Chiral separations of basic enantiomers were carried out by using a cationic cyclodextrin (CD), quaternary ammonium β-cyclodextrin (QA-β-CD), under counter-electroosmotic flow (counter-EOF) conditions. The special characteristics of using a cationic CD to separate cationic enantiomers is that the EOF can be reversed and the analyte-CD complexation is reduced. This is especially useful for chiral separation of cationic compounds, which strongly bind with neutral and anionic CDs (such as tricyclic amine compounds). The reduction in the binding constants between the CD and the cationic enantiomers makes it easier to control the optimum CD concentration. The application of the cationic CD also eliminated the peak tailing problem caused by electrodi-spersion. The effect of pH and the concentration of QA-βCD on chiral separation has been studied. At pH 3.02, no separation for any of the enantiomeric amines was observed. At pH 8.20, chiral separation of some tricyclic compounds was achieved at very high resolution due to the counter-EOF setup. At pH 11.6, most enantiomers were neutral and chiral separation of some bicyclic compounds can be obtained.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191209
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 77
    Electronic Resource
    Electronic Resource
    Application of heparin to chiral separations of antihistamines by capillary electrophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2119-2123 
    Details
    ISSN: 0173-0835
    Keywords: Chiral separations ; Antihistamines ; Heparin ; Capillary electrophoresis ; Enantiomers ; Capillary zone electrophoresis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: A study of the chiral separations of antihistamines, including pheniramine, chlorpheniramine, brompheniramine, carbinoxamine and doxylamine in capillary electrophoresis (CE) was accomplished using heparin as a chiral additive (CA) and phosphate buffer as the background electrolyte. Several factors were shown to affect both the selectivity and the migration time, including concentration of heparin, concentration of buffer, and the pH. A dual mechanism involving both inclusion complexation and ionic interactions with heparin is thought to be responsible for the chiral recognition. In the pH range of 2.6-3.5 and reversed polarity, baseline resolutions were obtained using a wide range of buffer and heparin concentrations. Typically, chiral resolution was obtained within 50 min.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191213
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 78
    Electronic Resource
    Electronic Resource
    Characterization of micelles by capillary electrophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2145-2150 
    Details
    ISSN: 0173-0835
    Keywords: Micelles ; Bile salts ; Capillary electrophoresis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: A practical approach for the characterization of pure micelles, and binary or ternary mixed micelles by capillary electrophoretic methods is presented. Interest is focused on the determination of mobility and composition of the micelles. The investigations are performed with bile salts, phosphatidylcho-lines and fatty acids. Pure bile salt micelles are characterized with the help of marking and displacement methods. Binary bile salt/phospholipid and ternary bile salt/phospholipid/fatty acid micelles are analyzed using capillary electrophoresis (CE) techniques with standard and improved UV detection, laser-induced fluorescence and electrospray ionization - mass spectrometry (ESI-MS). For both the binary and the ternary systems, only one stable mixed micellar phase is found with a high negative mobility.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191218
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 79
    Electronic Resource
    Electronic Resource
    Sodium dodecyl sulfate-capillary electrophoresis of proteins in a sieving matrix utilizing two-spectral channel laser-induced fluorescence detection (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2175-2178 
    Details
    ISSN: 0173-0835
    Keywords: Protein separation ; Sieving matrix ; Sodium dodecyl sulfate ; Capillary electrophoresis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: We report a method for protein labeling, separation by capillary electrophoresis in a polymer sieving matrix, and detection by laser-induced fluorescence. Different dyes are used to label standard and sample proteins. A two-spectral channel detector resolves fluorescence from the sample and standards. Comparison of the migration time of the sample and standards permits the precise determination of molecular weight, irrespective of variations in run-to-run migration times.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191222
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 80
    Electronic Resource
    Electronic Resource
    A theory for the electrophoretic separation of DNA in polymer solutions (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 3128-3136 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Polymer solutions ; DNA ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: We present a mathematical model of DNA capillary electrophoresis in polymer solutions based on nonentangling collisions between DNA and polymer molecules. Using videomicroscopy images of DNA migrating through polymer solutions, we propose a modified transient entanglement coupling mechanism for DNA separations that includes nonentangling DNA/polymer collisions. We show that a mathematical model based on individual nonentangling DNA/polymer collisions is able to predict the mobilities of DNA in solutions of low molecular mass polymer. We compare the model predictions to mobility data for separations of DNA in a range of concentrations for solutions of both hydroxypropylcellulose (Mw 100 000) and hydroxyethylcellulose (Mw 139 000). The model relies on one fitted parameter, the time constant for the interaction between the DNA and polymer molecules, which is based on the physical properties of DNA and polymers.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191814
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 81
    Electronic Resource
    Electronic Resource
    Capillary electrophoresis for simultaneous quantification of human proinsulin, insulin and intermediate forms (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 1475-1477 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Proinsulin conversion ; Intermediate forms ; Culture media purification ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Capillary electrophoresis (CE) for the simultaneous and precise quantification of human insulin (hI), proinsulin (hPI) and intermediate forms (des 31, 32; split 65-66 and des 64, 65), released in culture media by engineered cells, is described. Analytical conditions for standard proteins were optimized using a bare silica capillary (20 cm × 50 μm internal diameter). Proteins were monitored at 200 nm and separated at constant voltage. Culture supernatants (12-24 mL) were purified on Sep-Pak Vac C18 cartridges, recovered in 1 mL of acetonitrile:trifluoracetic acid mixture (60:40, v:v), concentrated, ultrafiltered and injected into CE. Protein recovery was 85 ± 14% (n = 5, mean ± standard deviation) with a sensitivity limit of 0.5 nmol/L in the culture media, corresponding to 2 fmol injected in 22 nL. Using the CE method, it was possible to detect and quantify, with precision and accuracy, the release of hPI, hI and intermediate forms directly in the cell culture media, and to compare the proteic pattern released from engineered cells transduced with different hPI gene constructs.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190843
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 82
    Electronic Resource
    Electronic Resource
    Analyte identification in capillary electrophoretic separation techniques (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2753-2776 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Capillary electrochromatography ; Analyte identification ; Spectrometric detection ; Review ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: A review on applications of on-line hyphenation in capillary electrophoresis and capillary electrochromatography for the identification of migrating analytes is presented. There is an urgent need for unambiguous analyte identification by combining spectral information and observed migration times, because the parameters influencing the migration times and separation efficiencies in these separation techniques are not easily controlled, especially when real samples containing unknown interferences have to be analyzed. The spectrometric techniques covered here are ultraviolet and visible radiation (UV/Vis) absorption, fluorescence including fluorescence line-narrowing spectroscopy, Raman spectroscopy, nuclear magnetic resonance and mass spectrometry. Attention is essentially confined to literature reports in which the extra information provided by the detector is really used for identification purposes, especially in real-life samples, while the interfacing as such and analyte detectabilities in standard solutions are only briefly discussed. This article covers an extensive fraction of the literature published on this topic until the beginning of 1998.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191604
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 83
    Electronic Resource
    Electronic Resource
    Use of capillary electrophoresis methods to characterize the pharmacokinetics of antisense drugs (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2861-2869 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Antisense DNA ; Phosphorothioate ; Pharmacokinetics ; Review ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: As antisense drugs become mature for clinical trials, analytical techniques to analyze antisense DNA in biological media for characterization of their pharmacokinetics will be in demand. Due to the superior resolving power of capillary gel electrophoresis (CGE), CGE will likely be a preferred method in quantifying intact oligonucleotides as well as the putative metabolic products. Nonetheless, biological mediums can influence the stability of the gel column, making a CGE assay time-consuming. In one approach, high-performance liquid chromatography (HPLC) was used to quantify the total amount of antisense compounds to increase the sample throughput and CGE was used to determine the relative percentage of the intact and metabolic species on specific samples. Alternatively, extensive sample pretreatment procedures were performed and the samples were quantified and characterized directly by CGE alone with the use of an internal standard. Both methods have been used to characterize the pharmacokinetics of antisense compounds. This review focuses on the instrumental and technical aspects of analyzing antisense DNA in biological mediums using CGE either as a single or a combined method towards better understanding of the pharmacokinetics of antisense DNA. Moreover, the newer analytical technologies of capillary electrophoresis (CE), which hold great potential to be used for pharmacokinetic applications, such as the replenishable sieving matrix combined with an innovative coupling approach and microchip CE, will also be explored.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191612
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 84
    Electronic Resource
    Electronic Resource
    Effects of various anionic chiral selectors on the capillary electrophoresis separation of chiral phenethylamines and achiral neutral impurities present in illicit methamphetamine (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2918-2925 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Chiral micelle ; Anionic cyclodextrins ; Methamphetamine and related compounds ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: In this study, various anionic chiral selectors were investigated for the capillary electrophoresis (CE) separation of six chiral phenethylamines and three achiral neutral impurities which are commonly identified in illicit methamphetamine. Analyses were carried out at pH 8 (high osmotic flow) with untreated capillaries using 25 mM chiral surfactant or 10 mM charged cyclodextrin. The chiral selectors included the micelle (R)-N-dodecoxycarbonylvaline (EnantioSelect (R)-Val-1)) (ES) and the cyclodextrins sulfobutyl(IV)-ether-β-cyclodextrin (SBE(IV)-β-CD) (BSB4), SBE(VII)-β-CD (BSB7), SBE(XII)-β-CD (BSB12), SBE(IV)-γ-CD (GSB-4), SBE(VII)-γ-CD (GSB-7), sulfated(XI)-α-cyclodextrin (SU(XI)-α-CD (AS11), SU(VII)-β-CD (BS7), SU(XII)-β-CD (BS12) and SU(XIII)-γ-CD (GS13). Enantiomeric and achiral selectivity strongly depends on the size of the CD, the average degree of substitution, and the type of substitution. ES exhibits good performance for the neutral solutes, but exhibits enantiomeric selectivity only for the α-hydroxyphenethylamines. GS13 provides the best overall enantiomeric selectivity. All fifteen solutes related to methamphetamine are simultaneously separated using BSB7.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191620
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 85
    Electronic Resource
    Electronic Resource
    Development of a simple high-performance capillary electrophoretic method with on-line mode in capillary derivatization for the determination of spermidine (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2986-2990 
    Details
    ISSN: 0173-0835
    Keywords: Biogenic amine ; Spermidine ; Capillary electrophoresis ; Incapillary derivatization ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: A new high-performance capillary electrophoretic (HPCE) method with an on-line mode in-capillary derivatization (ICD) procedure for determinations of some amines using 20 mmol/L sodium dodecyl sulfate (SDS) - 2 mmol/L o-phthalaldehyde (OPA) - 2 mmol/L N-acetylcysteine (NAC) - 20 mmol/L phosphate-borate buffer [9] has previously been shown. Although this technique offers direct fluorescence detection of free amines without any derivatization procedures before or after HPCE separation, the presence of spermidine (Spd) is difficult to detect due to low fluorescence intensity. The purpose of this study is to improve the detection sensitivity of Spd by reoptimizing this method with regard to the run buffer; the reoptimized method was applied to the determination of Spd in human plasma. To enhance the fluorescence intensity of the Spd signal, it is effective to use the run buffer in the presence of both β-cyclodextrin (β-CD: 8.8 mmol/L) and NAC at high concentration (16 mmol/L). By contrast, the intensity was remarkably decreased when SDS was used in the presence of β-CD. After ultrafiltrating (UF) spiked human plasma with Spd, UF plasma was directly analyzed using the reoptimized method. Spd peak was detected and separated from the other peaks of blank plasma. The present method gave good linearity (r = 0.999), reproducibility (3.85% coefficient of variation at 5 μmol/L level; n = 10) and specificity. The detection limit and lower limit of quantitation is for 0.2 μmol/L and 1 μmol/L, respectively.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191631
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 86
    Electronic Resource
    Electronic Resource
    Determination of bupivacaine and three of its metabolites in rat urine by capillary electrophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2997-3002 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Bupivacaine ; Bupivacaine metabolites ; Drug analysis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: A capillary electrophoretic (CE) method for the analysis of urinary extracts of the local anesthetic, bupivacaine, and its three main metabolites, desbutylbupivacaine, 3′-hydroxybupivacaine, and 4′-hydroxybupivacaine, in rat urine has been developed. The limits of detection were 0.22 μM for desbutylbupivacaine and bupivacaine, 0.15 μM for 3′-hydroxybupivacaine, and 0.16 μM for 4′-hydroxybupivacaine. The linear range was from 0.7 μM to 16.8 μM for all four compounds. Migration time and peak height reproducibilities, and extraction efficiencies were determined for all four compounds. Peak height reproducibilities (n = 5) for the overall method were improved through the use of prilocaine as an internal standard. Peak height reproducibilities were 5.6% RSD for desbutylbupivacaine and bupivacaine, and 9.9% RSD for 3′-hydroxybupivacaine and 4′-hydroxybupivacaine. Migration time reproducibilities (n = 5) were 2.4% for all compounds. Urine samples were collected from rats administered therapeutic doses of bupivacaine and extracted using a solid-phase extraction method (SPE). Separation of bupivacaine and its metabolites was achieved in 15 min.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191633
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 87
    Electronic Resource
    Electronic Resource
    Sex determination of foresic of forensic samples by polymerase chain reaction of the amelogenin gene and analysis by capillary electrophoresis with polymer matrix (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 76-79 
    Details
    ISSN: 0173-0835
    Keywords: Sex determination ; Forensic samples ; Amelogenin ; Capillary electrophoresis ; Polymer matrix ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The aim of this study was to validate an application of GenePrint™ Sex Determination System based on amplification of a section of the X-Y homologous gene amelogenin followed by capillary electrophoresis (CE) separation of polymerase chain reaction (PCR) products for gender testing of forensic DNA. It was found that subnanogram quantities of male and female DNA were correctly detected by this system. Experiments were performed to investigate the possibility of quantitating the X-Y chromosome-specific PCR products to disclose sex-mixed DNA samples. It was found that observed electrophoretic profiles correctly reflected an X-Y chromosome proporation of the DNA sample which was introduced into the PCR mix. The tested amelogenin PCR-CE system was successfully used for gender testing of a wide range of biological evidence including sex-mixed DNA samples from rape cases. These results demonstrate that the tested amelogenin PCR-CE system is a useful tool for gender determination of forensic DNA.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190114
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 88
    Electronic Resource
    Electronic Resource
    Genotyping of forensic short tandem repeat (STR) systems based on sizing precision in a capillary electrophoresis instrument (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 86-93 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Forensic ; Short tandem repeats ; Genotyping ; AmpFlSTR ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Automated fluorescence analysis of polymerase chain reaction (PCR)-amplified short tandem repeat (STR) systems by capillary electrophoresis (CE) is becoming an established tool both in forensic casework and in the implementation of both state and national convicted offender DNA databases. A new capillary electrophoresis instrument, the ABI Prism 310 Genetic Analyzer, along with the Performance Optimized Polymer 4 (POP-4) provides an automated and precise method for simultaneously analyzing ten flourescently labeled STR loci from a single PCR amplification kit, which provides a power of discrimination of approximately one in five billion from a single PCR amplification. Data are presented on sizing precision, sizing accuracy, and resolution for the STR loci in the AmpFlSTR Profiler™ kit. Sizing accuracy is highly dependent on the electrophoresis system, and therefore the reporting of alleles based on the nucleotide size obtained from an electrophoresis system is not recommended for forensic work. The precision of the 310 capillary electrophoresis system, coupled with software developed for automated genotyping of alleles based on the use of an allelie ladder, allows for accurate genotyping of STR loci. Sizing precision of ≤ 0.16 nucleotide standard deviation was obtained with this system, thus allowing for accurate genotyping of length variants that differ in length by a single nucleotide.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190116
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 89
    Electronic Resource
    Electronic Resource
    Capillary electrophoresis of peptides and proteins in fused-silica capillaries coated with derivatized polystyrene nanoparticles (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 262-269 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Proteins ; Peptides ; Derivatized polystyrene nanoparticles ; Coated capillary ; Hydrophilic surface ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: High-resolution capillary electrophoretic separation of proteins and peptides was achieved by coating the inner wall of 75 μm ID fused-silica capillaries with 40-140 nm polystyrene particles which have been derivatized with α-ω-diamines such as ethylenediamine or 1, 10-diaminodecane. A stable and irreversibly adsorbed coating was obtained upon deprotonation of the capillary surface with aqueous sodium hydroxide and subsequent flushing with a suspension of the positively charged particles. At pH 3.1, the detrimental adsorption of proteins to the capillary inner wall was suppressed efficiently because of electrostatic repulsion of the positively charged proteins from the positively charged coating which enabled protein separations with maximum efficiencies of 400 000 plates per meter. A substantial improvement of separation efficiency in particle-coated capillaries was observed after in-column derivatization of amino functionalities with 2,3-epoxy-1-propanol, resulting in a more hydrophilic coating. Five basic and four acidic proteins could be separated in less than 7 min with efficiencies up to 1 900 000 theoretical plates per meter. Finally, coated capillaries were applied to the high-resolution analysis of protein glycoforms and bioactive peptides.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190220
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 90
    Electronic Resource
    Electronic Resource
    Quantitative trace analysis of interleukin-3, interleukin-6, and basic model proteins using isotachophoresis-capillary zone electrophoresis with hydrodynamic counterflow (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 305-310 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Isotachophoresis ; Proteins ; Interleukins ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: A quantitative analytical technique to determine trace concentrations of recombinant human interleukin-3 (rhIL-3), recombinant human IL-6 (rhIL-6), and various basic model proteins is described using isotachophoresis-capillary zone electrophoresis (ITP-CZE). Proteins were separated on coated fusedsilica capillaries using a commercial capillary electrophoretic system modified for the application of isotachophoretic preconcentration with hydrodynamic counterflow. The effect of injection time and isotachophoretic focusing time was investigated and compared with predictions from existing mathematical models. Good linearity of the calibration graphs (r 〉 0.995) was observed for all investigated proteins. The limit of quantification was in the 10-8 M range using UV detection at 200 nm. Within-day and between-day precison of peak area ranged between 1 and 6%. Precision was unaffected by isotachophoretic preconcentration. In conclusion, the described method is feasible to quantify trace concentrations of rhIL-3, rhIL-6, and basic proteins. Potential applications comprise issues of pharmaceutical quality control.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190227
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 91
    Electronic Resource
    Electronic Resource
    A diagnostic test for scrapie-infected sheep using a capillary electrophoresis immunoassay with fluorescent-labeled peptides (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 409-414 
    Details
    ISSN: 0173-0835
    Keywords: Prion protein ; Immune complexes ; Capillary electrophoresis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Scrapie in sheep and goats is the prototype of transmissible spongiform encephalopathies found in humans and animals. A feature of these diseases is the accumulation of rod-shaped fibrils in the brain that form from an aggregated protein. This protein (PrPSC) is a protease-resistant form of a normal host cell protein. When the aggregated protein is denatured in sodium dodecyl sulfate (SDS) and β-mercaptoethanol, a monomer form of ∼27 kDa molecular mass is observed. A competition immunoassay to detect PrPSC from scrapie-infected sheep was developed using free zone capillary electrophoresis with laser-induced fluorescence (LIF) for detection and flourecein-labeled sysnthetic peptides from PrPSC. Antibodies were made to each respective peptide and used in the competition assay. The fluorescent-labeled peptides bound to the antibody were separated from the unbound peptides using 200 mM Tricine, pH 8.0, containing 0.1% n-octylglucoside and 0.1% bovine serum albumin (BSA). The amount of antibody that would bind ∼50% of the fluorescent-labeled peptide was determined for each peptide. When unlabeled peptide was added to the assay, ∼2 fmoles of the peptide could be measured. When PrPSC extracted from infected sheep brain was added to the assay, approximately 135 pg of PrPSC could be detected. When preparations from normal sheep were assayed, there was little or no competition for the bound peptides. Assays using two of the peptides, peptides spanning amino acid positions 142-154 and 155-178, clearly differentiated scrapie-positive sheep from normal animals. This assay is a new method that can be used to diagnose scrapie and, possibly, other transmissible spongiform encephalopathies in animals and in humans.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190308
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 92
    Electronic Resource
    Electronic Resource
    Separation of 4-color DNA sequencing extension products in noncovalently coated capillaries using low viscosity polymer solutions (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 224-230 
    Details
    ISSN: 0173-0835
    Keywords: DNA sequencing ; Capillary electrophoresis ; Low viscosity media ; Bare capillaries ; Polydimethylacrylamide ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: A low viscosity (ca. 75cp) solution using polydimethylacrylamide (PDMA) was developed for separating DNA sequencing extension products by capillary electrophoresis (CE). This medium gave a length-of-read (LOR) value of approximately 600 bases in about 2 h using four-color sequencing in 50 μm capillary at 42°C under a field of 160 V/cm. This medium also works in bare capillaries by noncovalently coating the surface to suppress both electroosmotic flow (EOF) and DNA-capillary wall interactions, and eliminates the need for complicated covalent coatings. At least 100 successive sequencing runs were performed in the same capillary by simply pumping fresh medium after every run, without requiring any reconditioning of the capillary surface between runs. The thermal stability of the noncovalent coating can be improved by adding small amounts of high molecular weight PDMA to the separation medium. The advantages of low viscosity separation media and uncoated capillaries are of paramount importance to develop high-throughput instruments for DNA sequencing.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150190215
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 93
    Electronic Resource
    Electronic Resource
    Parallelism between width and asymmetry of peaks of rigid, spherical particles in capillary zone electrophoresis using polymer solutions (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 1620-1624 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Polymer solution ; Peak dispersion ; Peak asymmetry ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Peak width and peak asymmetry of rigid spherical particles in the size range of 3-100 nm radius (R) were measured in capillary zone electrophoresis (CZE), using buffered uncross-linked polyacrylamide of Mr 5.0 × 106. Polymer concentration-dependent spreading of peak width and peak asymmetry were found to parallel one another. The parallelism holds whether the particle size is within the “small” (R 〈 20 nm) or “large” (R 〉 20 nm) size ranges previously found to differ in the mechanism of particle size dependent retardation of electrophoretic migration (S. P. Radko and A. Chrambach, Electrophoresis 1996, 17, 1094-1102). In application to the “small” particle size range, the parallelism between band width and band asymmetry can be qualitatively interpreted to be consistent with the Giddings-Weiss mechanism (G. H. Weiss et al., Electrophoresis 1996, 17, 1325-1332) of electrophoresis in polymer-containing media which postulates a dependence of band width and band asymmetry on the equilibrium between “stationary” and “mobile” states of the particle.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191017
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 94
    Electronic Resource
    Electronic Resource
    Identification of maize lines via capillary electrophoresis of zeins in isoelectric, acidic buffers (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 1738-1741 
    Details
    ISSN: 0173-0835
    Keywords: Isoelectric buffers ; Capillary electrophoresis ; Zeins ; Maize ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Modified capillary zone electrophoresis of zeins in strongly acidic, isoelectric buffers is reported for screening of maize (Zea mays L.) lines. The optimized background electrolyte contained 40 mM aspartic acid (pH = pI = 2.77), 8 M urea and 0.5% short-chain hydroxyethylcellulose (Mn 27000 Da) (apparent pH in 8 M urea: 3.9). Due to the low conductivity of such a buffer (0.7 mmhos), separations can be carried out at 800 V/cm, even in relatively large bore capillaries (50 μ ID), ensuring good sensitivity. The zein patterns thus obtained are species-specific and allow easy identification of all maize lines tested. No adsorption of proteins to the silica wall is observed and high reproducibility in peak areas and transit times is obtained. The relatively slow migration time (ca. 30 min), even under such a high voltage gradient, is attributed to the paucity of basic amino acid residues typical of zeins, leading to an unfavorable charge/ mass ratio due to the modest net positive charge at the operative pH.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191035
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 95
    Electronic Resource
    Electronic Resource
    Development of separation systems for polynuclear aromatic hydrocarbon environmental contaminants using micellar electrokinetic chromatography with molecular micelles and free zone electrophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2090-2094 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Polynuclear aromatic hydrocarbons ; Laser-induced fluorescence ; Molecular micelles ; Environmental analysis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Of four systems available from the literature, based on cyclodextrins, dioctyl-sulfosuccinate, bile salts, and molecular micelles consisting of oligomers of undecylenic acid, the most successful separation system in our hands is based on the molecular micelles, oligomers of sodium undecylenic acid (OSUA). We have employed organic additives of acetonitrile, acetone, and tetrahydrofuran in achieving separations of polyaromatic hydrocarbons (PNAs) using molecular micelles. Generally, successful separations are achieved with 20-40% composition as the organic additive in an 8 mM borate buffer. We separated 16 PNAs with 20% tetrahydrofuran in a system of 8 mM borate and 0.125 g/ 10 mL (ca. 6.25 mM) of OSUA. Typical extracts of environmental samples contain additional analytes besides the typical 16 target compounds. Among these are the nitrogen-containing aromatics that can act as cations under conditions of low pH and additional compounds that can act as anions under basic conditions in free-zone electrophoresis. These additional classes of analytes are separated by capillary zone electrophoresis/laser-induced fluorescence detection using a frequency-doubled laser operated at 257 nm.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191208
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 96
    Electronic Resource
    Electronic Resource
    Nonaqueous capillary electrophoresis  -  its applicability in the analysis of food, pharmaceuticals and biological fluids (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2179-2186 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Nonaqueous ; Food ; Pharmaceuticals ; Biological fluids ; On-line capillary electrophoresis - mass spectrometry ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The use of nonaqueous electrophoresis media for the application of capillary electrophoresis in the analysis of food, pharmaceuticals and biological fluids is reviewed. Some of the applications are discussed in detail and the benefits of using nonaqueous media in these cases are outlined. Three new applications within pharmaceutical analyses are presented. In these methods either a simple sample pretreatment by dilution with methanol (determination of chlorhexidine in a cream) or selective on-line capillary electrophoresis mass spectrometry (methods for identification of seizure drugs or opium alkaloids) are used. The choice of organic solvents and electrolytes for nonaqueous capillary electrophoresis are discussed. Furthermore, validation data obtained using capillary electrophoresis based on the nonaqueous principle are listed and discussed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191223
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 97
    Electronic Resource
    Electronic Resource
    Pressure-assisted and pressure-programmed capillary electrophoresis/electrospray ionization time of flight - mass spectrometry for the analysis of peptide mixtures (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2200-2206 
    Details
    ISSN: 0173-0835
    Keywords: Peptide mixtures ; Pressure programming ; Capillary electrophoresis ; Electrospray ionization ; Mass spectrometry ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Pressure assisting and pressure programming the inlet of the capillary electrophoresis instrument were used for the analysis of peptide mixtures and protein digests using capillary electrophoresis/electrospray ionization - mass spectrometry (CE/ESI-MS). CE/ESI-MS of peptide mixtures and tryptic digests of proteins was studied using three different types of capillary columns: (i) a freshly aminopropylsilane (APS)-treated column, (ii) an untreated column, and (iii) a degraded APS-treated column. To maintain a constant and adequate buffer flow toward the CE capillary outlet for stable CE and ESI operation, low pressure was applied to the inlet of the CE when an untreated or degraded APS capillary was used. By programming the inlet pressure, CE/ESI-MS analysis time was reduced to 1/3 of its original time. The utility of this technique is demonstrated by CE/ESI-MS analysis of a hemoglobin variant (hemoglobin-S) and its tryptic digests. Identification of the mutant peptide in the tryptic digest of hemoglobin-S was achieved by collision-induced dissociation (CID) of the protein digests using CE/ESI time of flight - mass spectrometry (TOF-MS).
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191226
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 98
    Electronic Resource
    Electronic Resource
    Size separation of sodium dodecyl sulfate complexes of human plasma proteins by capillary electrophoresis employing linear polyacrylamide as a sieving polymer (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2308-2316 
    Details
    ISSN: 0173-0835
    Keywords: Sodium dodecyl sulfate electrophoresis ; Capillary electrophoresis ; Protein size separation ; Human plasma proteins ; Linear polyacrylamide ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Electrophoretic conditions to separate sodium dodecyl sulfate (SDS) complexes of human plasma proteins according to their size differences, by capillary electrophoresis employing linear polyacrylamide as a sieving matrix (LPA-CE), have been examined. Using the optimized separation conditions, SDS complexes of human plasma proteins not treated with reducing agents were separated into about 40 peaks and shoulders within 60 min. The molecular mass values of major peaks in a separation pattern were estimated from a plot of molecular mass and migration time for standard proteins and some of the major plasma proteins have been identified on the pattern. The electrophoretic conditions were successfully applied for the analysis of proteins in immunoglo-bulin G (IgG) myeloma sera.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191310
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 99
    Electronic Resource
    Electronic Resource
    Protein profile characterization of bacterial lysates by capillary electrophoresis (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2317-2323 
    Details
    ISSN: 0173-0835
    Keywords: Protein profile ; Bacteria ; Capillary electrophoresis ; Lysate ; Enterobacteriaceae family ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: A fast and reproducible method was developed to characterize cell lysates by their electrophoretic profiles using capillary electrophoresis (CE). Characteristic and reproducible patterns were recorded for each bacterial strains when “dynamic sieving” CE, using a polymer solution in the capillary, was applied to distinguish four strains of the Enterobacteriaceae family. The electropherograms showed distinct differences when comparing them to the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) protein profiles. This is certainly a result of the differences in the separation principles and in the detection methods of the two techniques.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191311
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 100
    Electronic Resource
    Electronic Resource
    Simultaneous measurement of α-amylase and glucoamylase activities in sake rice koji by capillary electrophoresis of sodium dodecyl sulfate-protein complexes and activity measurement of glucoamylase by in-capillary enzyme reaction method (1998)
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 2331-2337 
    Details
    ISSN: 0173-0835
    Keywords: Capillary electrophoresis ; Sodium dodecyl sulfate-protein complexes ; Protein separation ; α-Amylase ; Glucoamylase ; Sake rice koji ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Capillary electrophoresis (CE) of sodium dodecyl sulfate (SDS)-protein complexes using a nongel sieving matrix (CE-SDS) has been applied to the simultaneous analysis of α-amylase and glucoamylase activity in sake rice koji which is employed for the brewing of sake. α-Amylase and glucoamylase in sake rice koji extracts were successfully analyzed by CE-SDS. α-Amylase and glucoamylase were found to have molecular masses of 53 000 and 63 000 Da, respectively, as determined by the migration times of eight standard proteins. These values agree with those determined by SDS-polyacrylamide gel electrophoresis (PAGE). The results of CE-SDS method were compared with those achieved by the official method. The relative standard deviations (RSD) of the α-amylase and glucoamylase activities by CE-SDS were less than 5.0% in both intra-day and inter-day experiments. An electrophoretic analysis of products of an enzyme reaction of a substrate by in-capillary reaction was also useful for the activity measurement of glucoamylase in sake rice koji. p-Nitrophenyl-β-D-maltoside (PNP-Mal) was employed as a substrate and p-nitrophenyl-β-D-glucopyranoside (PNP-Glu) was the product of the enzyme reaction. The glucoamylase activity of sake rice koji samples gave the good linear relationship with the peak area observed in the in-capillary enzyme reaction method. The glucoamylase activity in sake rice koji was measured by either CE-SDS or the in-capillary enzyme reaction more easily than by the official method. Both methods can be applied to the routine quality control of α-amylase and glucoamylase activities in sake rice koji.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150191313
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...