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  • 1980-1984  (480)
  • 1983  (480)
  • Biochemistry and Biotechnology  (404)
  • Gas chromatography
  • Nuclear reactions
  • 1
    ISSN: 1432-2072
    Keywords: Halazepam ; Desmethyldiazepam ; Benzodiazepines ; Pharmacokinetics ; Gas chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Halazepam and its major metabolite desmethyldiazepam (DMDZ) can be reliably quantitated in human plasma following single doses of halazepam. After addition of appropriate internal standards, halazepam and DMDZ are extracted directly into an organic solvent at physiological pH. The organic extract is separated, evaporated to dryness, reconstituted, and directly chromatographed using a 50:50 methyl:phenyl silicone column (SP-2250) and an electron-capture detector. After a single 40 mg oral dose of halazepam, the parent compound appears in plasma only transiently and at low levels. DMDZ appears in higher concentrations and is slowly eliminated. During multiple-dose therapy with halazepam, DMDZ will be the major active substance in blood.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Archives of toxicology 54 (1983), S. 311-321 
    ISSN: 1432-0738
    Keywords: Toxaphene ; Distribution ; Mice ; Autoradiography ; Gas chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Series of female virgin and pregnant albino mice were i.v. injected with14C-labelled- or unlabelled toxaphene (16 mg/kg b.w.). After survival times ranging from 1 min to 32 days the toxaphene distribution in the body was studied using whole-body autoradiography and capillary gas-chromatography. Autoradiographic studies have shown that after an initial accumulation in the liver, brown fat, lung, brain, kidney, and ovaria (corpora lutea) there was a gradual redistribution of radioactivity to the white fat within 4 h postinjection. The labelling was then decreasing rapidly and only negligible amounts of the radioactivity were present in the adipose tissue after 32 days. In the fetus only the liver and adrenals showed a distinct labelling. A specific and persistent accumulation of the label was detected in some zones of the adrenal cortex suggesting a possible direct interference of toxaphene with adrenal steroid hormone synthesis. The gas chromatographic pattern of toxaphene-derived residues in the tissue samples resembled that of the technical toxaphene, but was changing in different tissues with the time. The liver chromatograms indicated more extensive formation of metabolites.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    International archives of occupational and environmental health 53 (1983), S. 101-108 
    ISSN: 1432-1246
    Keywords: Biological exposure test ; Exercise ; Gas chromatography ; Hippuric acid ; Humans ; Isotachophoresis ; Laboratory exposure ; o-Cresol ; Rest ; Toluene ; Urine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The urinary excretion of hippuric acid and o-cresol was studied after respiratory exposure of human volunteers to approximately 80 ppm (306 mg/m3 ± SD 13) of toluene for 2 h under different work loads (0, 50,100, 150 W, respectively, during 30-min periods). The diet before and after exposure varied. An isotachophoresis method for the determination of hippuric acid is described. The correlation between the total urinary excretion, excretion rate and concentration of hippuric acid, and the respiratory uptake of toluene was poor or non-existing. The same was true for the excretion of o-cresol, which 4 h after exposure was concluded amounted to 0.03–0.26% of the toluene uptake. Thus, after a short-time exposure neither metabolite proved to be a reliable measure of individual toluene uptake at varying workloads or food intake in combination with low exposure levels.
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  • 4
    ISSN: 1432-1238
    Keywords: Gas chromatography ; Head-space analysis ; CCl4 intoxication ; Hyperventilation therapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A head-space gas chromatographic method for the determination of carbon tetrachloride in human blood is described. Standard samples with 0.5 ml whole blood containing different concentrations of CCl4 were analyzed at column temperatures ranging from 50° to 90°C. Advantages of this method include high sensitivity, simplicity in handling, rapid achievement of reliable results, accuracy and low costs. The practicability of this analytical method was studied in a patient following suicidal oral ingestion of a lethal dose of carbon tetrachloride.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 34 (1983), S. 20-26 
    ISSN: 1570-7458
    Keywords: Dioryctria abietella ; Cone pyralid ; Lepidoptera ; Pyralidae ; Sex pheromone, (Z,E)-9,11-tetradecadienyl acetate ; Single sensillum recordings ; Electroantennography ; Gas chromatography ; Mass spectrometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé L'analyse en chromatographie gazeuse associée à une détection électroantennographique a montré que l'acétate (Z,E)-9,11-tétradécadiényle (Z,E)-9,11–14:Ac est l'un des composants de la phéromone de Dioryctria abietella Schiff (Lepid.: Pyralidae). Couplage chromatographie en phase gazeuse spectrometrie de masse a montré la présence d'acétate tétradécadiényle avec un spectre de masse et un indice de rétention identiques au Z,E-9,11–14:Ac Un récepteur cellulaire sensible à la fois au Z,E-9,11–14:Ac et à un extrait de la femelle a été identifié sous l'antenne du mâle. Les analyses des antennogrammes et de la cellule isolée ont étayé la caractérisation du composant de la phéromone comme étant Z,E-9,11–14:Ac. Un récepteur cellulaire additionnel sensible à l'acétate (Z.)-9-tétradécadiényle et à l'acétate (Z.E.)-9,12-tétradécadiényle a été trouvé sur l'antenne du mâle, mais il n'était pas activé par l'extrait de la femelle. Sur le terrain Z,E-9,11–14:Ac, présenté seul, attirait des nombres importants de mâles de D. abietella. L'addition de l'acétate (Z)-9-tétradécényle a inhibé l'attraction des mâles par les pièges.
    Notes: Summary Gas chromatographic analyses coupled with electro-antennographic detection indicated that (Z,E)-9,11-tetradecadienyl acetate (Z,E-9, 11–14:Ac) is a pheromone component of the cone pyralid Dioryctria abietella. Gas chromatographic-mass spectrometric analyses confirmed the presence of a tetradecadienyl acetate with mass spectrum and retention index identical to Z,E-9,11–14:Ac. A receptor cell sensitive to both Z,E-9,11–14:Ac and the female extract was identified on the male antenna. An additional receptor cell sensitive to (Z)-9-tetradecenyl acetate and (Z,E)-9,12-tetradecadienyl acetate was found on the male antenna but was not activated by the female extract. In the field Z,E-9,11–14:Ac presented alone attracted significant numbers of male D. abietella. Addition of (Z)-9-tetradecenyl acetate inhibited the attraction of males to traps.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 17 (1983), S. 33-36 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Preparative scale chromatography ; Capacity ; Dual-step separation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The capacity of dual-step preparative chromatographic separation systems is considered. It is shown that dualstep separation makes it possible to enhance the capacity of preparative installations as compared with single- and dual-stage purification of the compounds.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 17 (1983), S. 44-46 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Natural gas analysis ; Poropak N
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A simple gas chromatographic method is described for the rapid analysis of natural gas using thermal conductivity detectors and programmed-temperature operation of a single Poropak N column. The method permits the determination of nitrogen, carbon dioxide and hydrocarbons containing one to seven carbon atoms.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 17 (1983), S. 553-559 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Open-tubular (capillary) columns ; Immobilized liquid phases ; Thick-film columns ; Diffusion coefficients
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The influence of the liquid phase film thickness in open-tubular (capillary) columns on the individual resistance-to-mass-transfer terms and on the overall column efficiency is examined from the theoretical point of view. Methods for the calculation of the diffusion coefficients are discussed.
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  • 9
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Open-tubular (capillary) columns ; Immobilized liquid phases ; Thick-film columns ; GC-FTIR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The performance of a column prepared with an immobilized (chemically bonded) methylsilicone phase having a film thickness of 5μm is investigated in detail. Due to their high sample capacity, such columns are particularly useful when directly coupling gas chromatography with spectroscopic techniques such as Fourier-transform infrared spectroscopy. Thick-film columns can even be used with thermal conductivity detectors.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 17 (1983), S. 600-604 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Retention index ; Alkyl benzenes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The additivity concept in the retention index system of Kovats has been examined for a series ofn-alkylbenzenes and theiro- andp-monosubstituted nitro-, amino-, and chloro-derivatives. Anomalous behaviour is exhibited by the first three members of the series on both polar and non-polar stationary phases. For addition of a methylene group ton-propylbenzene or ap-substituted derivative, it is found that the retention increment, Δl CH2, approaches 100 units. However, the strong inductive effect of the group in the ortho position and the steric effects apparent in ano-substituted alkylbenzene lead to large variations of retention increment upon addition of-CH2-to the alkyl chain. A study ofn-alkylbenzene retention on Apiezon L and Carbowax 20M over a wide range of temperatures has verified the linearity of the retention increment with temperature and has revealed that this gradient increases with increasing carbon side-chain length for the first few members of the series, thereafter becoming constant. Functional retention increments, Δlx, for substitution of nitro-, amino- and chloro-groups into the benzene ring are given.
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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 17 (1983), S. 691-692 
    ISSN: 1612-1112
    Keywords: Dichlorophenol isomers ; Sodium benzenesulfonate ; Gas chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary It is difficult to separate all the dichlorophenol isomers as free phenols by gas-liquid chromatography. However they were effectively separated on 4,4′-dimethoxyazoxybenzene (liquid crystal), and all the isomers were separated appreciably well on sodium 1-naphthalenesulfonate, 2-naphthalenesulfonate and dodecylbenzenesulfonate.
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 17 (1983), S. 65-69 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Oxygenates ; Fused-silica capillary columns
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A method of analysing gasolines that contain oxygenates has been developed. The method uses a single fusedsilica capillary column and gives quantitative data for the oxygenates and the hydrocarbons in one analysis.
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  • 13
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Trace analysis ; GC-concentration ; Enrichment factor ; Theoretical evaluation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Based on gas chromatographic retention data obtained on a given adsorbent and at a given trap efficiency at different temperatures new equations are proposed for the evaluation of the enrichment factor. These equations are suitable under various preconcentration conditions such as: equilibrium saturation, complete trapping and permissible losses. Compared to known expressions for the evaluation of the enrichment factor the equations suggested consider the band broadening of the impurity in a trap causing a loss of the substance at the adsorption stage and dilution of the sample during desorption when the desorbed impurities are directed into the gas chromatographic column without intermediate freezing out in an graphic column without intermediate freezing out in an empty tube. The new equations may be used to select the optimum preconcentration conditions providing the necessary sensitivity.
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 17 (1983), S. 191-194 
    ISSN: 1612-1112
    Keywords: Thermal treatment of MgO and MgCO3 ; Adsorption properties ; Gas chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The changes in the chromatographic properties of MgO and MgCO3 due to thermal treatment was investigated. The experimental results show that thermally treated MgO and MgCO3 can be used as stationary phase for the gas-adsorption chromatography of hydrocarbon mixtures.
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  • 15
    ISSN: 1612-1112
    Keywords: Esterification in aqueous solution ; n-Butyl esters of fatty acids ; Gas chromatography ; Fatty acid analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The esterification of C1−C8 fatty acid in aqueous solutions and in the presence of sulfuric or hydrochloric acid and with n-butanol is described. It has been established that the esterification can be used for the quantitative determination of these fatty acids in the concentration ratio range of [H2O]/[n-BuOH]=0.01–5.3. In the concentration ratio range of 0.01–0.8 the water present does not interfere. In the concentration range of above 0.8 anhydrous sodium sulfate is used for binding the water, in the amount of [Na2SO4.anh.]/[H2O]≥0.2.
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  • 16
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 17 (1983), S. 472-476 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Liquid stationary phase ; Liquid phase bleeding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The theory of the evaporation of the liquid stationary phase is elaborated and experimentally verified. On the basis of this theory the role played by the losses in the amount of liquid phase present is quantitatively determined. General techniques are examined which minimize the losses; these techniques are based on saturating the incoming carrier gas with liquid phase vapours and raising the pressure of the carrier gas in the column, e.g. by connecting a capillary to the column outlet in order to offer resistance to the gas flow. The application of these techniques ensures stable performance of the gas chromatographic columns using a volatile liquid phase.
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  • 17
    ISSN: 1612-1112
    Keywords: Esterification in aqueous solution ; iso butyl esters of C1–C20 fatty acids ; Gas chromatography ; Fatty acid analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary C1–C20 carboxylic acids have been esterified in aqueous solutions with i-butanol. Gas chromatographic analyses have been performed from a single chromatogram. It has been established that esterification in the concentration range of [H2O]/[i-BuOH]=0.01–10.3 can be utilized for the quantitative determination of these carboxylic acids. The presence of water does not interfere in the range of [H2O]/[i-BuOH]=0.01–1.03. In the cases of [H2O]/[i-BuOH]〉1.03, anhydrous sodium sulfate has been used for binding the water, in an amount of [Na2SO4]anh./[H2O]≥0.2.
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  • 18
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 17 (1983), S. 241-243 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Detectors ; Flame ionization detector ; History of chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary On the occasion of the 25-year anniversary of its invention, this article summarizes the events which led to the development of the flame ionization detector.
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  • 19
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Average molecular polarizability ; Retention index ; Polycyclic aromatic hydrocarbons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The Kováts retention indices of 10 polycyclic aromatic hydrocarbons were determined on SE-30, OV-101, SE-52, OV-7 and OV-17 stationary phases. A significant correlation has been found between the retention indices and the average molecular polarizabilities of the analyzed substances. Equations were derived for the direct determination of the average molecular polarizabilities from the retention index values. The influence of the temperature on this relationship is also indicated.
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  • 20
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 17 (1983), S. 418-420 
    ISSN: 1612-1112
    Keywords: Separation of metal chelates ; Gas chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A very good separation of the acetylacetonate of AL-(III), Cr(III) and Co(III) has been obtained by gas chromatography, on a column containing OV-17 silicone oil as the stationary phase.
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  • 21
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 6 (1983), S. 4-10 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Ion mobility detector ; Plasma chromatography ; Selective detection ; Quantitative analysis ; Halogenated compounds ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An ion mobility detector that has been specifically developed for interfacing with capillary gas chromatography is investigated in the negative ion mode. Like the electron capture detector, to which this instrument is closely related, the ion mobility detector shows an enhanced response to low molecular weight halogenated compounds when a small quantity of oxygen is doped into the make-up gas flow. Under O2 doping conditions, the device can operate in a reactant ion monitoring mode responding universally to compounds capable of capturing thermal electrons and in a tunable selective product ion mode providing increased selectivity over that achieved by the ECD. At an oxygen concentration of 0.5%, minimum detectable amounts as low as 600 femtograms have been realized for carbon tetrachloride. Selectivity of chloro- versus bromo- compounds is demonstrated using a mixture of p-dichlorobenzene and p-dibromobenzene.
    Additional Material: 7 Ill.
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  • 22
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 6 (1983), S. 11-15 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary, glass ; ECD ; Halocarbons in water, 0.1-10 ppb ; 0.5-2 μl injected on-column ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Interest in monitoring halogenated organics in drinking water and natural surface and ground water in the low ppb range continues to grow. There is a tendency to include still more volatile halocarbons, the trace determination of which is known to be rather demanding. This prompted us to re-examine the feasibility of large-volume direct aqueous injection onto capillary columns, coupled with ECD. A primary problem was to avoid simultaneous elution of water with halocarbons, since water suppresses the ground current of the ECD. The following measures contributed to the solution of this problem.Apolar, extremely inert, columns are required to elute water completely, and even before very light halocarbons. Their coatings have to be far thicker (≍ 5 mUm) than commonly employed thick films since they must permit isothermal analysis at a column temperature around 100°C in order to ensure rapid and complete elution of water. Finally, it is essential that sampling be carried out on-column for two reasons: diffusion of water vapor in the injector, resulting in delayed elution, is then eliminated, and peak distortion during splitless injection is avoided.Although we now know that persilylated columns with immobilized coatings withstand routine water injections, more longterm experience is needed to provide detailed recommendations for the handling of these columns.
    Additional Material: 2 Ill.
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  • 23
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 6 (1983), S. 34-35 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary, glass ; Samples with varying water content ; Retention times correlated with water content ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
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  • 24
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 6 (1983), S. 241-246 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Fused silica capillary columns ; Cobalt-60 gamma radiation ; Immobilized phase ; Crosslinking ; Column activity ; Temperature Stability ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Fused silica capillaries deactivated with D4 and coated with OV-1 were subjected to cobalt-60 gamma radiation in order to elucidate the effect of incident radiation on column performance. The chromatographic performance of these open tubular columns in which OV-1 was polymerized in situ was found to be dependent on the dosage of radiation and was evaluated before and after the irradiated columns were rinsed with solvent. Of the radiation dosages employed, 3 MRad produced superior chromatographic performance coupled with very favorable residual surface activity.
    Additional Material: 3 Ill.
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  • 25
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 6 (1983), S. 247-254 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary, fused silica ; Screening for basic drugs with retention indices differing by only four units ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Capillary columns offer the toxicologist several advantages over packed columns. We have presented a highly reproducible screening procedure based on the retention index system and have shown the use of capillary columns for routine quantitation. We are currently expanding the use of these columns in our laboratory and predict that they will be in routine use by most toxicologists in the near future.
    Additional Material: 9 Ill.
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  • 26
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    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 6 (1983), S. 255-263 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary, glass, fused silica ; Two-dimensional technique ; Residue analysis in food ; Organophosphorus pesticides ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two-dimensional gas chromatography with two capillary columns of different polarity (SP 2100 and OV 225) is used for pesticide residue analysis in food samples. By means of “live chromatography” applying pneumatic switching technique according to Deans, unequivocal identification of 57 organophosphorus pesticides in food samples is achieved at trace concentrations. The instrument is equipped with only one injection port and one flame photometric detector. On-line data processing is very helpful, especially in calibration and checking the system's reliability with the multitude of test compounds. The complete pesticide residue analysis including clean-up of about six food samples can be completed by one person in 8 hours.
    Additional Material: 6 Ill.
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  • 27
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    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 6 (1983), S. 273-274 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Solvent effect ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
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  • 28
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    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 6 (1983), S. 317-319 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary column, fused silica ; Drug screening ; Fused silica capillary column ; Toxicology ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
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  • 29
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    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 6 (1983), S. 436-440 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary, fused silica ; Superox-4 pretreatment, deactivation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 5 Ill.
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  • 30
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    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 6 (1983), S. 480-487 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary column ; Residue mixtures ; Inlet characteristics ; Injection procedure ; Repeatability ; Linearity ; Quantification ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Residue mixtures of pesticides in foods which were difficult to separate by packed-column gas chromatography were determined by capillary gas chromatography and electron capture detection. Manual injections of sample and reference standard were made with a 10 μL syringe on a septum-enclosed, split/ splitless inlet system. Optimal peak height repeatability (± 3%( was achieved with three-μL injections which were made within time periods of four hours or less. The average linearity coefficient (slope( obtained for detector response as a function of solution concentration was 1.1.
    Additional Material: 6 Ill.
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  • 31
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    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 6 (1983), S. 497-500 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary column, fused silica ; On-column injection ; Solvent polarity ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 5 Ill.
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  • 32
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    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 6 (1983), S. 501-504 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary columns ; Van Deemter curves ; Thick film columns ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
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  • 33
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    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 6 (1983), S. 504-507 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary columns ; Effluent splitting ; Polyimide ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 5 Ill.
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  • 34
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    Journal of High Resolution Chromatography 6 (1983), S. 510-511 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Optically active compounds ; Determination of trace amounts ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
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  • 35
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    Journal of High Resolution Chromatography 6 (1983), S. 567-568 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Solvent effect ; Headspace analysis ; Trace analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
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  • 36
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    Journal of High Resolution Chromatography 6 (1983), S. 101-103 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary, fused silica ; GC/MS ; Drugs of abuse ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 5 Ill.
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  • 37
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    Journal of High Resolution Chromatography 6 (1983), S. 133-139 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary, glass ; Advantages of very thick coatings ; Separation efficiency correlated with film thickness ; Preparation of columns with very thick coatings ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It has become common practice with capillary columns to call film thicknesses of 0.1 - 0.3 μm regular or standard, whereas 0.3 - 1.0 μm is considered to denote thick films. Consequently, films with thickness beyond 1μm (we have explored the range up to 8.0 μm) may be termed very thick. Increasing film thickness, at least to about 5 μm, brings important additionl advantages primarily in terms of loading capacity. Columns with very thick coatings may replace the traditional SCOT columns thanks to at least equivalent loading capacity combined with higher separation efficiency, and better stability characteristics. Additional advantages are increased retention, essential for the analysis of very volatile substances, and increased elution temperature, providing a basis for direct water injection.We observe that TZ (the separation number) drops to roughly 50% when the film thickness is increased by a factor of 300 from 0.025 to 8.0 μm, provided TZ is measured with a standard flow of hydrogen. The reduction is only 30% when the thick-film colums are run with individual optimization with nitrogen as a carrier gas. In contrast to standard columns, very thickly coated columns show slightly increased separation efficiency with nitrogen at drastically reduced flow rate. The HETP increases very slightly in the indicated range of flim thickness. This contradicts widespread theoretical expectations, which probably account for the fact that very thick coatings have so far been neglected. Since the preparation of very thick coatings involves some deviations from the standard procedure, complete and detailed instructions are given.
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  • 38
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    Journal of High Resolution Chromatography 6 (1983), S. 153-155 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary, glass ; Immobilization of moderately polar phases ; Combination of surface bonding and crosslinking ; Vinyl groups in the support surface ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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  • 39
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary column ; Automated analysis ; Solvent vapor ; Gas sampling ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Solvent vapors in air may be measured with capillary gas chromatographic columns. By using large diameter columns and sample loops of approximately the same internal diameter, the column may be connected directly to the gas sampling valve. This approach eliminates the use of a splitter or cryogenic trapping and allows low levels to be measured. By operating the column at high velocity, column efficiency is sacrificed for increase in speed.
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  • 40
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    Journal of High Resolution Chromatography 6 (1983), S. 232-235 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Inlets ; Solvent effect ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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  • 41
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary, glass ; Dynamic versus static leaching ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It is well known that removal of metal ions from the glass surface greatly improves both the thermal stability and the adsorption characteristics of glass capillary columns. Usually metal ions are removed from a glass surface by acid leaching; in particular, the static leaching procedure with hydrochloric acid is used very often for the preparation of glass capillary columns. This paper discusses the results of an investigation into dynamic leaching. Special attention is paid to those factors which affect the adsorption properties of the leached surface. The importance of the non-specific adsorptivity of the capillary surface due to changes of surface properties induced by the leaching process is pointed out.
    Additional Material: 7 Ill.
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  • 42
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    Journal of High Resolution Chromatography 6 (1983), S. 281-282 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Si-OR, bonded stationary phase ; Change of physical state ; Retention mechanism ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
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  • 43
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    Journal of High Resolution Chromatography 6 (1983), S. 292-299 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Fused silica capillary columns ; GC/MS/DS ; Cryotrapping of organics ; Cryofocusing of organics ; Trace organic analysis ; Priority pollutants ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A 30 m, 0.25 mm ID, fused silica capillary column at temperatures from -60 to -100°C has been shown to be a quantitative trap for organic compounds with volatilities ranging from that of 1, 1 -dichloroethene that of chlorobenzene. This type of “whole column cryotrapping” provided sharp peaks (peak width approximately 4-7 seconds) for all compounds at a trapping temperature of -80°C and with high carrier gas pressures and linear velocities (30 psi and 110 cm/s, respectively). Whole column cryotrapping possesses great simplicity, chromatographic efficiency (no trapping loop connections), and a built-in indicator of quality assurance for trapping efficiency (i.e., peak shape). These advantages are extremely attractive and are indicative of the fact that the potential of this approach has not yet been fully appreciated.
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  • 44
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    Journal of High Resolution Chromatography 6 (1983), S. 386-387 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary columns ; On column injection ; Movable injector ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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  • 45
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    Journal of High Resolution Chromatography 6 (1983), S. 388-389 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Fused silica capillary micro-packed columns ; Separation characteristics ; Application ; Separation of hydrocarbons ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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  • 46
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    Journal of High Resolution Chromatography 6 (1983), S. 444-445 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Open-tubular columns ; Reduced diameter ; High pressure ; Coating reservoir ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
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  • 47
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    Journal of High Resolution Chromatography 6 (1983), S. 448-450 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary column ; Solute focussing ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 48
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    Journal of High Resolution Chromatography 6 (1983), S. 561-563 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Fused silica capillary ; On-column injection ; Rotary valve ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
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  • 49
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    Journal of High Resolution Chromatography 6 (1983), S. 564-565 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary, fused silica ; Splitless injection ; Trace analysis ; EPA phenols ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
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  • 50
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    Journal of High Resolution Chromatography 6 (1983), S. 36-37 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary column ; Cryogenic focusing ; On-column, pre-column trapping ; Volatile aroma compounds ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
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  • 51
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    Journal of High Resolution Chromatography 6 (1983), S. 42-44 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Mg(NO3)2 .6H2O as stationary phase ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
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  • 52
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    Journal of High Resolution Chromatography 6 (1983), S. 60-63 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary column ; Cold silanization ; Medium polarity columns ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Silane-coupling agents, commonly used for fiberglass reinforced plastics (FRP), were applied for deactivation of silanol sites in glass capillary columns prior to coating with mediumpolarity phases such as Carbowax and Superox. The columns, prepared in a two-stage process in the case of glass (acidic leaching and drying, dynamic cold silanization followed by static coating with the phase) or a one stage process in the case of fused silica, gave the best results when deactivation and hence wettability were induced by glycidoxypropyltrimethoxy silane.
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  • 53
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    Journal of High Resolution Chromatography 6 (1983), S. 228-231 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Sample introduction ; Splitless injection ; On-column injection ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 54
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    Journal of High Resolution Chromatography 6 (1983), S. 319-321 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Supercritical fluid chromatography ; Small diameter capillary columns ; Static coating at elevated temperature ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Tab.
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  • 55
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    Journal of High Resolution Chromatography 6 (1983), S. 328-332 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Fused silica (capillary) columns ; Bonded (cross-linked ) phases ; Hydrocarbon analysis ; Retention index data ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Tab.
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  • 56
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    Journal of High Resolution Chromatography 6 (1983), S. 366-370 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Fused silica capillary column ; Chiral phase ; Amino acid enantiomers ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Heliflex Chirasil-Val, a modified form of the original Chirasil-Val phase coated on fused silica capillary, has been investigated with regard to its resolution efficiency and the separation profile for various enantiomeric derivatives of amino acid. The best results could be obtained with TFA-Et derivatives by reason of the relatively low column temperature required.
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  • 57
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    Journal of High Resolution Chromatography 6 (1983), S. 390-391 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Dispersive interactions ; Inductive interactions ; Polycyclic aromatic hydrocarbons ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
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  • 58
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    Journal of High Resolution Chromatography 6 (1983), S. 422-426 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary, glass ; Stationary phase, polar ; DEGA ; Residue analysis of pesticides ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polydiethylene glycol adipate (DEGA) has been successfully used as stationary phase for residue analysis by glass capillary gas chromatography. A specially stabilized version of the phase yields a good polar column which is stable up to 250°C when used in temperature programmed cycles. The paper lists 90 pesticides that have been successfully chromatographed in ng quantities on a DEGA column.
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  • 59
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    Journal of High Resolution Chromatography 6 (1983), S. 442-443 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Cyclodextrin polymer beads ; Double retention mechanism ; Interaction energy ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
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  • 60
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    Journal of High Resolution Chromatography 6 (1983), S. 40-42 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary columns ; Splitless Injection ; Drug analysis ; Concentration dependence of retention values ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 61
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    Journal of High Resolution Chromatography 6 (1983), S. 185-188 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Injection ; Inlets ; Volume overloading ; Concentration overloading ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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  • 62
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Residue analysis ; Fenvalerate ; Fabric protectant ; Woolen cloth ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is described for the determination of fenvalerate (cyano(3-phenoxyphenyl)methyl 4-chloro-α-(1-methylethyl)-benzeneacetate) residues on woolen cloth. The fenvalerate was Soxhlet-extracted from the treated fabric with acetone for four hours at a reflux rate of six solvent exchanges per hour. The fenvalerate residue was determined by gas-liquid chromatography with a flame ionization detector. The results were quantitated by comparing integrator counts obtained from extracts of treated samples with those obtained from known standards. The method was sensitive to 0.00054% fenvalerate by weight. Recoveries from fabric treated with 0.00054% to 0.215% averaged 94.8%. The response of the detector was linear over a 400-fold range of fenvalerate concentrations.
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  • 63
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    Journal of High Resolution Chromatography 6 (1983), S. 213-215 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary column ; HPLC sample work-up ; Valeriana celtica L ; Essential oil ; Nepetalactone, isovaleric acid ; Feline attractant ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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  • 64
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    Journal of High Resolution Chromatography 6 (1983), S. 269-272 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Retention indices ; Specific retention volumes ; n-Alkanes ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The choice of stationary phase for gas chromatography is dictated by the nature of the analytes. Polarity and selectivity are known to play an important role. This paper suggests equations for calculation of specific retention volumes of any compounds from their retention indices.
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  • 65
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    Journal of High Resolution Chromatography 6 (1983), S. 279-281 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary column, glass ; Packed column ; Retention data ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
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  • 66
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    Journal of High Resolution Chromatography 6 (1983), S. 392-393 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary columns ; Hydrogen carrier gas ; Pt-Ir tubing ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
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  • 67
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    Journal of High Resolution Chromatography 6 (1983), S. 507-509 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary column, glass ; GC/MS ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 5 Ill.
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  • 68
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    Journal of High Resolution Chromatography 6 (1983), S. 661-665 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Injector systems ; On-column injection ; Liquid chromatography, HPLC ; Dibenzothiophene oxide and dioxide ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Analytical methods are described for identification and monitoring of the oxygenated metabolites of dibenzothiophene. Since such compounds are thermolabile, GC analysis is seen to be hardly feasible with conventional injectors such as all-glass moving needle or splitless injectors. Only on-column injection gives no degradation products. In addition, reversed-phase HPLC is particularly suitable for the analysis of the sulfone or sulfoxides of dibenzothiophenes.
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  • 69
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    Journal of High Resolution Chromatography 6 (1983), S. 595-604 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; GC/MS ; Pyrolysis GC ; Pyrolysis MS ; Headspace sampling ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pyrolysis gas chromatography (P/GC) has been successful in differentiating coal tar pitches which are used in the manufacture of high temperature graphite materials [1,2]. In the present study, coal tar and petroleum pitches received from five suppliers were readily differentiated using three distinct methods of polymer analysis: dynamic headspace and pyrolysis gas chromatography mass spectrometry (DH/GC/MS and P/GC/MS, [3]), and pyrolysis mass spectrometry (P/MS, [4,5]). All of these methods are appropriate for the analysis and pattern recognition study of coal and petroleum products; however, methods which incorporate GC usually necessitate long analysis times and are subject to problems associated with gas chromatographic reproducibility (e.g. active sites [6], and nonconstant retention times). As a fingerprint analysis method, P/MS is rapid and ideally suited to computerized pattern recognition study of pitches due to the simple format of P/MS data (computer tabulation of normalized intensities versus masses); whereas, in the present study, the normalized peak area versus retention time date from DH/GC/MS and P/GC/MS analyses were not suitable for direct input to a computerized pattern recognition analysis program, (due to non-constant retention times and improper data format). One limitation is that P/MS does not provide positive identification of thermally evolved products (as can DH/GC/MS and P/GC/MS) due to the complexity of the spectra of a mixture of compounds produced by P/MS. Within the limits of the commercial instrumentation and computer programs used in this study, a combination of all three techniques provided the greatest capability for the differentiation of the five coal tar and petroleum based pitches studied.
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  • 70
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    Journal of High Resolution Chromatography 6 (1983), S. 623-624 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary columns ; On-column injection ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 71
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    Journal of High Resolution Chromatography 6 (1983), S. 621-622 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Multiplex GC ; Vacancy chromatograms ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 72
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    Biotechnology and Bioengineering 25 (1983), S. 341-349 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The effects of sodium bicarbonate concentration, population density, and temperature on the maintenance of an outdoor monoculture of the cyanobacterium Spirulina platensis were studied. A clear response by Spirulina to the concentration of bicarbonate was evident, with 0.2M bicarbonate representing the lowest concentration in which a monoculture could be maintained. When the temperatures fell during the winter period to some 20-25°C below the optimum for Spirulina, Chlorella sp. gradually increased and became the dominant species in the culture. Raising the temperature by covering the pond with transparent polyethylene resulted in a sharp decline in the population of Chlorella, and a gradual resumption of species dominance by Spirulina. In winter, there was an inverse relationship in the pond between the population density of Spirulina and the extent of contamination by Chlorella sp.; but no such effect was observed under field conditions at temperatures higher than 25°C.
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    Biotechnology and Bioengineering 25 (1983), S. 403-416 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A simple approach was developed to determine the half-saturation coefficient for dissolved oxygen (KDO) for three bacteria by maintaining a constant oxygen concentration in continuous culture, and employing a dynamic method to obtain the specific growth rate (μ) for each species. Measurement of μ at selected dissolved oxygen concentrations (DO) resulted in a typical Monod curve for a plot of μ vs. DO. Values for KDO and μmax were obtained from the Lineweaver-Burk reciprocal plot. The bacteria studied included representative strains of three microorganisms isolated in pure culture from poorly settling activated sludge: two filamentous microorganisms, Sphaerotilus natans and a second Sphaerotilus sp., and an unidentified floc-forming microorganism. The KDO values obtained for Sphaerotilus sp., S. natans, and the floc former were 0.014, 0.033, and 0.073 mg/L, respectively. Dual species competition experiments were conducted in continuous culture under low and high DO conditions. Successful growth competition by these microorganisms under DO-limiting conditions was consistent with experimentally determined KDO values. The finding of lower KDO values for the two Sphaerotilus species, compared to the floc former, confirmed the hypothesis that these filamentous microorganisms can outgrow floc-forming microorganisms in activated sludge when DO in the aeration basin is low.
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  • 74
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A working system for studying the effects of factors involved in the chemical nature of microcarriers on cell attachment, spreading, and growth was established. The system is based on polyacrylamide beads, prepared by the emulsion polymerization technique. Sieved beads of desirable mean diameter were derivatized to generate controlled amounts of primary and tertiary amino groups. These microcarriers were used for the propagation of four different cell strains: BHK, MDCK, CEF, and MRC-5. It was found that BHK cells attach and spread significantly faster on primary amino-derivatized beads than those with tertiary amino groups, and at a lower degree of charging. Cell yields of MDCK cells (with pronounced epithelial morphology) propagated on primary amino-derivatized beads were higher than that obtained for the tertiary amino-derivatized microcarriers. On the other hand, CEF and MRC-5 cells (with pronounced fibroblast morphology) achieved higher cell yields on the tertiary amino-derivatized microcarriers.
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  • 75
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Fungal α-amylase (E.C. 3.2.1.1) and glucoamylase (E.C. 3.2.1.3) were chemically attached to separate reactor modules made from Microporous Plastic Sheet (MPS). Immobilization of enzymes and subsequent chemical reactions were accomplished by pumping reactants through the sheet, i.e., perpendicular to the surface. The expressed activity of the reactor modules was ca. 800 U/g for both fungal α-amylase and glucoamylase. The kinetics and short-term effects of pH and temperature on the expressed activity of the immobilized enzymes were investigated. Using commercially available DE-42 corn syrup at 50% dissolved solids, half-lives of 2000 and 5000 h were achieved for glucoamylase and fungal α-amylase, respectively. The reactors were operated at 50°C and at pH 4.3 for glucoamylase and 5.5 for fungal α-amylase. A typical DE-62 corn syrup product was continuously produced in a two-stage reactor system by pumping the feedstock through the glycoamylase reactor and then through the fungal α-amylase reactor. Saccharide distributions at each stage were controllable to ±0.2%.
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  • 76
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    Biotechnology and Bioengineering 25 (1983), S. 559-568 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Potentiometric and amperometric measurements were made with microbial fuel cells containing E. coli or yeast as the anodic reducing agent and glucose as the oxidizable substrate. The catalytic effects of thionine and resorufin on the anode reaction were investigated. Results on the potentiometry, polarization, and coulombic output of the cells support a mediator-coupled mechanism for the transfer of electrons from the organism to the electrode in preference to a mechanism of “direct” electrochemical oxidation of glucose or its degradation products. Experiments with 14C-labeled glucose show that when a microbial fuel cell produces a current under load, exogenous glucose is metabolized to produce 14CO2. The Coulombic yields of the cells indicate a high degree of energy conversion in these systems.
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  • 77
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: With carrot cells grown in semicontinuous culture with phosphate as limiting nutrient. Dougall and Weyrauch (1980) found that the steady-state culture density was different at different dilution rates. They suggested that the yield constant for biomass was different at different dilution rates. Here the yield constant for biomass for PO43-, NH4+, Mg2+, and glucose-limited semicontinuous cultures has been measured directly at two dilution rates. The yield constants for PO43-, NH4+, and Mg2+ but not for glucose are different at the two dilution rates. The effects of pH and temperature on the biomass yield constant was measured to extend the number of system parameters examined. Biomass yield constant was changed little with change from 25 to 28°C or from pH 4.2 to pH 5.5. The steady-state levels of anthocyanin were also measured. The responses of anthocyanin levels to the system parameters are different to the biomass responses. The data suggest that at different values of each of the system parameters, the composition and metabolic activities of the cells at steady state in semicontinuous cultures are different.
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  • 78
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 4 Ill.
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  • 79
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    Biotechnology and Bioengineering 25 (1983), S. 627-630 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
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  • 80
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    Biotechnology and Bioengineering 25 (1983), S. 967-983 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In an effort to alter the filamentous morphology of Penicillium chrysogenum cells, a technique was developed to confine the growth of the mycelia to porous celite beads. The pore matrix of these beads was found to be very effective for entrapping mycelial cells and spores. The entrapped spores were used to initiate the fermentations in shake flask cultures. Significant increases in final cell densities were obtained in the confined cell cultures reaching up to 60 g/L cells. This is nearly double the cell concentration attainable in free cell cultures grown in the absence of beads. Cell loadings up to 0.55 g cells per bead were obtained in the confined cell cultures. In the later stages of the fermentations, the specific oxygen uptake rates in the confined cell cultures were found to decrease with respect to free cell cultures.
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  • 81
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    Biotechnology and Bioengineering 25 (1983), S. 417-436 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: E. Coli was cultivated in batch and continuous operations in the presence of an antifoam agent in stirred-tank and in single- and ten-stage airlift tower reactors with an outer loop. The maximum specific growth rate, μm, the substrate yield coefficient, Yx/s, the respiratory quotient, RQ, substrate conversion, Us, the volumetric mass transfer coefficient, KLa, the specific interfacial area, a, and the specific power input, P/VL, were measured and compared. If a medium is used with a concentration of complex substrates (extracts) 2.5 times higher than that of glucose, a spectrum of C sources is available and cell regulation influences reactor performance. Both μm and YX/S, which were evaluated in batch reactors, cannot be used for continuous reactors or, when measured in stirred-tank reactors, cannot be employed for tower-loop reactors: μm is higher in the stirred-tank batch than in the tower-loop batch reactor, μm and Yx/s are higher in the continuous reactor than in the batch single-stage tower-loop reactor. The performance of the single-stage is better than that of the ten-stage reactor due to the inefficient trays employed. A reduction of the medium recirculation rate reduces OTR, Us, Pr, and YX/S and causes cell sedimentation and flocculation. The volumetric mass transfer coefficient is reduced with increasing cultivation time; the Sauter bubble diameter, ds, remains constant and does not depend on operational conditions. An increase in the medium recirculation rate reduces kLa. The specific power input, P/VL, for the single-stage tower loop is much lower with the same kLa value than for a stirred tank. The relationship kLa vs. P/VL evaluated for model media in stirred tanks, can also be used for cultivations in these reactors.
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  • 82
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    Biotechnology and Bioengineering 25 (1983), S. 497-511 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A mathematical model for glucose-to-ethanol fermentation at high yeast cell concentrations was developed. The feasibility of improving fermenter productivity over that of a conventional continuous-stirred-tank fermenter by using multiple stage reactors and yeast cell recycling was predicted by computer simulation. The optimum size distribution for multistage fermentors was obtained for different glucose feedstream concentrations and different glucose conversion levels. Productivity increases over a single-stage reactor ranged from 1.2-2.0 times. The use of yeast cell recycling to increase cell concentration and productivity increases of over 4.0 times that of a system without recycling.
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  • 83
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    Biotechnology and Bioengineering 25 (1983), S. 541-557 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Twenty-two different yeasts were screened for their ability to ferment both glucose and cellobiose. The fermentation characteristics of Candida lusitaniae (NRRL Y-5394) and C. wickerhamii (NRRL Y-2563) were selected for further study because their initial rate of ethanol production from cellobiose was faster than the other test cultures. C. lusitaniae produced 44 g/L ethanol from 90 g/L cellobiose after 5-7 days. When higher carbohydrate concentrations were employed, fermentation ceased when the ethanol concentration reached 45-60 g/L. C. lusitaniae exhibited barely detectable levels of β-glucosidase, even though the culture actively fermented cellobiose. C. wickerhamii produced ethanol from cellobiose at a rate equivalent to C. lusitaniae; however, once the ethanol concentration reached 20 g/L, fermentation ceased. Using p-nitrophenyl-β-D-glucopyranoside (pNPG) as substrate, β-glucosidase (3-5 U/mL) was detected when C. wickerhamii was grown anaerobically on glucose or cellobiose. About 35% of the β-glucosidase activity was excreted into the medium. The cell-associated activity was highest against pNPG and salicin. Approximately 100-fold less activity was detected with cellobiose as substrate. When empolying these organisms in a simultaneous saccharification-fermentation of avicel, using Trichoderma reesei cellulase as the saccharifying agent, 10-30% more ethanol was produced by the two yeasts capable of fermenting cellobiose than by the control, Saccharomyces cerevisiae.
    Additional Material: 7 Ill.
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  • 84
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: When carrot cell cultures, after growth in semicontinuous culture, were transferred to media containing excess nutrients, they grew at different rates. The growth rates were generally higher after semicontinuous culture at higher dilution rates. There appears to be a limit on dilution rate above which growth rate does not increase. These changes were also displayed by clones from the parental culture. The possibility that these changes in growth rate reflect a need for the cultures to adapt to their new conditions is discussed. The growth rates of the cultures is markedly increased at 25°C compared with 22°C with little further increase at 28°C. Growth rate is altered by less than 20% when pH is changed from 4.5 to either 5.5 or 4.2. The rates of anthocyanin accumulation by the cultures were similar under all conditions tested except at 22°C. They were larger than the rates of dry weight accumulation. In contrast, the amounts of anthocyanin accumulated in the clones and in the parental cultures grown at pH 5.5 instead of pH 4.5 were very different. The observations were interpreted as showing that the clones differ in the rate of metabolism but not in the rate of synthesis of anthocyanins and that at pH 5.5 the rate of metabolism of anthocyanins but not the rate of synthesis is higher than it is at pH 4.5. The use of semicontinuous cultures as a source of inoculum for batch cultures rather than as a source of biomass for extraction of chemicals is discussed.
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  • 85
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    Biotechnology and Bioengineering 25 (1983), S. 619-622 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
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  • 86
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    Biotechnology and Bioengineering 25 (1983), S. 631-646 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In the microbial production of useful products, it is important to understand the allocation of substrate energy for maintanance, growth, and product formation. Methods are presented to obtain point and 95% confidence interval estimates for the true growth yield parameter, true product yield parameter, and the maintenance parameter. Methods are presented which allow all data to be used simultaneously for those cases where more than the minimum number of measurements are made at each specific growth rate (or dilution rate). Three estimation methods and two forms of the energy allocation equations are investigated. Point estimates are similar for the three methods, but interval estimates are considerably larger for one of the three methods. The results depend on the form of the equations.
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  • 87
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    Biotechnology and Bioengineering 25 (1983), S. 687-697 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A novel technique for settling microorganisms has been described. The technique involves adding a dense, inert powder to a suspension of microorganisms under conditions where flocculation of the microorganism with the inert poweder occurs. The flocs formed are small and relatively dense and settle rapidly. Suspensions of Saccharomyces cerevisiae yeast have been flocculated with several different inert seed materials achieving rapid settling and separations of up to 99.9%. Nickel powder was used as a seed material for most experiments described here, and iron sand showed promise as a cheaper seed for large-scale use. The degree of flocculation and cell separation obtained depended largely on the seed concentration and the components in solution. Temperature and pH had little effect. When the method was initially applied to a practical fermentation, flocculation was poor because of inhibiting compounds in the fermentation medium, but modification of the technique produced good flocculation in the medium.
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  • 88
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    Biotechnology and Bioengineering 25 (1983), S. 735-744 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The characteristics of horseradish peroxidase (HRP) immobilized onto Sepharose by a photochemical-initiated graft copolymerization are presented. Active copolymers were synthesized using different amounts of glycidylmethacrylate (GMA), bisacryloylpiperazine (BAP), or 1,3,5-hexhydrotriacryloyl-s-triazine (HTsT) as functional monomer. The activities, the K′m values (pGMA) copolymers: 0.53-0.76 × 10-4M; pBAP copolymers: 0.90-1.4 × 10-4; pHTsT copolymers: 1.8-2.6 × 10-4M and the thermal stabilities of the enzyme copolymers were strictly connected to the type of polymer. By varying the polymer amount present in a given copolymer, significant differences were found in the thermostability properties of pBAP and pHTsT copolymers both when checked in water or in phosphate buffer. No differences were found for pGMA copolymers. The samples in which there are the lowest pBAP or pHTsT content resulted the most stable. The activity retained after 240 min at 60°C by free HRP and pGMA-HRP was 30% whereas by pBAP-HRP and pHTsT-HRP it was 50 and 75% of the original. Operational stability of the materials was in agreement with thermostability data. These results are discussed in terms of enzyme microenvironment which is strongly affected by the different network of the three polymers.
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  • 89
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    Biotechnology and Bioengineering 25 (1983), S. 745-759 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This article is concerned with the development of a model to plan a strategy for an enzymatic batch process where enzyme is subjected to deactivation described by the inverted linear decay model. The particular system studied is the enzymatic hydrolysis of penicillin to 6-amino penicillanic acid (6 APA), but the model can be utilized with other batch systems as long as the decay of the immobilized enzyme (IME) preparation is described by the inverted linear decay model. The model developed is eminently practical and simple and several example of its application are shown. Experimental data obtained in a small pilot plant batch recirculated reactor on the average are well fitted by this model. For IME systems whose decay is best described by the first-order decay model, it is not possible to use the same approach.
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  • 90
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    Biotechnology and Bioengineering 25 (1983), S. 781-796 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A structured model for the penicillin fermentation is presented. This model includes three different cell types: (1) hyphae tips, (2) penicillin-producing cells, and (3) degenerated, metabolically inactive cells. Cell degeneration has been described previously as a gradual loss of cytoplasmic material by endogenous metabolism. The rate at which such loss of cytoplasm (and activity) proceeds can be expressed as a linear function of the specific growth rate. At growth rates above some minimum value (0.0115 h-1) cell degeneration can be prevented. This model served as the control basis during open-loop as well as closed-loop computer control of the fermentation. Closed-loop control was achieved through feedback information of biomass concentration using a filtration probe and was required when complex nutrients contributed significantly to the overall biomass production.
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  • 91
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    Biotechnology and Bioengineering 25 (1983), S. 863-865 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 92
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    Biotechnology and Bioengineering 25 (1983), S. 1677-1678 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 1 Ill.
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  • 93
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    Biotechnology and Bioengineering 25 (1983), S. 1693-1700 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The efficiency of lipid synthesis by ethanol-grown yeasts is characterized using the coefficient of the lipid energetic yield (η1). This coefficient is defined as the fraction of energy in an organic substrate that is converted to lipids. The advantages of η1 compared with the “fat coefficient” (Fs) as well as the biomass energetic yield (η) compared with Ys are discussed.
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  • 94
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    Biotechnology and Bioengineering 25 (1983), S. 1747-1772 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The effects of the inability of suspension-feeding protozoa to collect bacteria over the whole range of sizes in the bacterial size distribution were examined by constructing mathematical models based on this assumption. Systems of suspension-feeding protozoa grown on both growing and nongrowing bacteria were examined in both batch and continuous culture. The models were able to predict three experimental observations common in such systems. Some additional features of the systems which should be useful in interpreting results of experiments with suspension feeding protozoa and in designing new experiments were predicted, also.
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  • 95
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    Biotechnology and Bioengineering 25 (1983), S. 1359-1372 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Three established cell lines were examined for growth on a newly developed microcarrier which consists of glass beads. The cells were simultaneously exmined for growth on commercially available microcarriers made from DEAE-dextran and from plastic. Cell yields on the glass microcarriers were comparble to the cell yields on the commercially available products. Cells grown on the glass microcarriers were easily separated from the substratum by trypsinization (as were the cells grown on the plastic substratum) while the cells grown on the DEAE-dextran particles were much more trypsin resistant. After removal of cells from the glass microcarriers, the cells reattached and spread out in plastic flasks as readily as cells harvested from monolayer. Scanning electron microscopy revealed dramatic differences in the appearence of the cell grown on the glass microcarriers and cells grown on the DEAE-dextran microcarriers. On the glass microcarriers, cells attached to the substratum through lond, slender filopodia while on the DEAE-dextran microcarriers, the entire edge of the cell appeared to be in contact with the substratum. This dissimilarity in attachment could underly the difference in sensitivity to trypsin-mediated detachment. Finally, the glass microcarriers were washed after being used once and retested for their ability to support cell growth a second time. Nearly identical results were obtained with the reprocessed beads as with previously unused ones.
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  • 96
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    Biotechnology and Bioengineering 25 (1983), S. 1071-1082 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Bamboo carbohydrates were hydrolyzed with commercial amylases and a mixture of fungal culture broths containing cellulolytic and hemicellulolytic enzymes. The effects of cooking temperature and the size of fiber particles were also investigated. It was found that the higher the cooking temperature, the higher the rate of sugar formation and the lower the viscosity of the slurry. Additions of cellulose and hemicellulose digesting enzymes increased the sugar yield and decreased the viscosity of both the cooked and noncooked slurries. A smaller size of particle appeared to favor the average saccharification rate. Although glucose, xylose, and cellobiose were present in the hydrolysates, only 50% of the total carbohydrate was digested, and 78.9% of this was converted to reducing sugars. The alcohol efficiency for the fermentation of cooked and noncooked mashes by Saccharomyces was about 85%.
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  • 97
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    Biotechnology and Bioengineering 25 (1983), S. 1083-1093 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The production of the extracellular nuclease secreted by Staphylococcus aureus (Foggi strain) was studied in a fermentor in an attempt to improve yield and allow large-scale production of the enzyme. In shake flask cultures, 600 units/mL of the enzyme were produced routinely. However, only 450 units/mL of the enzyme at best were obtained in a small-scale fermentor (3 L). The supplementation of the air supply to the fermentor with carbon dioxide [20% (v/v)] increased levels of enzyme in the culture medium to 770 units/mL. Subsequently, this result was reproduced in larger fermentors (10 and 150 L). The possible mechanisms of the effect of carbon dioxide upon the growth of Staphylococcus aureus (Foggi) and the production of the enzyme are discussed.
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  • 98
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    Biotechnology and Bioengineering 25 (1983), S. 1109-1126 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Direct anaerobic bioconversion of cellulosic substances into ethanol by Clostridium thermocellum ATCC 27405 has been carried out at 60°C and pH 7.0 (initial for 100 L) under continuous sparging of oxygen free nitrogen in a culture vessel. Raw bagasse, mild alkali-treated bagasse, and solka floc were used as substrates. The extent of conversion of raw bagasse (cellulose, 50%; hemicellulose, 25%; lignin, 19%) was observed as 52% (w/w) and 79% (w/w) in the case of mild alkali and steam-treated bagasse (cellulose, 72%; hemicellulose, 11%; lignin, 12%), respectively. Use of bagasse concentration above 10 g/L showed a decreased rate in ethanol production. An inoculum age between 28-30 h and cell mass content of 0.027-0.036 g/L (dry basis) were used. The results obtained with raw and pretreated bagasse have been compared with those of highly pure Solka Floc (hemicellulose, 10%). Studies on the product inhibition indicated a linear fall of the percent of survivors with time. An Arrhenius type correlation between the cell decay rate constant and the product concentration was predicted. Even at low levels, the inhibitory effects of products on cell viability, the specific growth rate, and extracellular cellulase enzyme were observed.
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  • 99
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 25 (1983), S. 1175-1179 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 100
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 25 (1983), S. 1181-1186 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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