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  • Analytical Chemistry and Spectroscopy  (1,947)
  • Physics  (864)
  • 1
    Electronic Resource
    Electronic Resource
    Is Multidimensional High Performance Liquid Chromatography (HPLC) an Alternative in Protein Analysis to 2D Gel Electrophoresis? (2000)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 259-265 
    Details
    ISSN: 0935-6304
    Keywords: Proteomics ; protein analysis ; multidimensional HPLC ; ion-exchange chromatography ; reversed phase chromatography ; comprehensive HPLC ; two-dimensional HPLC ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The interactive modes of High Performance Liquid Chromatography (HPLC) of proteins provide a platform for the construction of a multidimensional HPLC system coupled to mass spectrometry. We present a system composed of both anion and cation exchanger columns, in the first dimension, and n-octadecyl bonded 1.5 μm nonporous silica columns in the second dimension. Both columns are operated under gradient conditions. A system suitability test with standard proteins showed that the total analysis can be performed within about 20 minutes. The fractions taken from the ion exchanger column are directly analyzed within one minute on the reversed phase column at a high flow rate. Two reversed phase columns are applied and operated alternatively: while the first column performs the separation within one minute, the analytes leaving the first dimension are enriched in an on-column focusing mode on top of the second column. The sample clean-up and enrichment is performed on a novel type of restricted access cation exchanger column with internal sulfonic acid groups and external diol groups. The columns exhibit a molecular weight exclusion limit for globular proteins of about 15 kDa. Our next studies will be directed towards the analysis of proteins and peptides from extracts of fibroblasts.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 2
    Electronic Resource
    Electronic Resource
    Carbon-13 NMR spectra of some labdane diterpenoids (1981)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 17 (1981), S. 301-302 
    Details
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Carbon-13 signal assignments of the labdane diterpenoids phlogantholide-A, its diacetate and isophlogantholide-A are reported. The assignments of the 13C NMR signals of 14-deoxyandrographolide and its diacetate, made earlier, have now been confirmed by lanthanide shift studies on the former and also by 13C spectral studies on anhydroandrographolide diacetate and 14-deoxy-11,12-didehydroandrographolide diacetate.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270170416
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  • 3
    Electronic Resource
    Electronic Resource
    A gas chromatographic mass spectrometric assay for plasma trifluoperazine concentrations following single doses (1982)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 9 (1982), S. 186-190 
    Details
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A gas chromatographic mass spectrometric assay using selected ion monitoring is described which permits the determination of trifluoperazine in plasma at concentrations ranging from 0.078 to 5.0 ng ml-1. It relies on the extraction of trifluoperazine and the internal standard, prochlorperazine or the tetradeuterated analogue of trifluoperazine, form basified plasma with a n-pentane/2-propanol solvent mixture. Following the evaporation of organic solvent, the residue is reconstituted in a small volume of methanol. Suitable aliquots were anlysed by the combined technique of gas chromatography/electron impact mass spectrometry with a data system. The described procedure is specific and enables the quantitation of 78 pg ml-1 of the drug with a coefficient of variation 〈7%. The method has demonstrated sufficient sensitivity to permit pharmacokinetic and bioavailability studies after a single 5 mg oral dose.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200090503
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  • 4
    Electronic Resource
    Electronic Resource
    Identification with liquid chromatography-ionspray mass spectrometry of the metabolites of the enantiomers N-methyl dextrorphan and N-methyl levorphanol after rat liver perfusion (1993)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 22 (1993), S. 226-234 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: To gather more information on stereochemical factors in the hepatic disposition of organic cations, mass spectrometry coupled to liquid chromatography was used to determine the identity of the metabolites excreted in bile after isolated rat liver perfusions with the quaternary ammonium derivatives of the enantiomeric drugs dextrorphan and levorphanol. Ionspray mass spectrometry was chosen for its soft ionization and absence of thermal degradation of labile compounds. The drugs were labelled with a stable (2H) isotope and mixed with unlabelled drugs to create an artificial isotope pattern in the mass spectrum and facilitate the recognition of unknown metabolites. In mass spectra that were recorded under normal conditions, fragmentation was absent and metabolites of N-methyl dextrorphan and N-methyl levorphanol were visible as parent-ion ‘doublets’. Collision-induced fragmentation studies were performed to support the identification of the metabolites. For N-methyl dextrorphan the glucuronide, the glutathione conjugate and the glucuronide of the N-demethylated metabolite were found in bile. For N-methyl levorphanol the glucuronide, the glutathione conjugate, the sulphate conjugate and the glucuronide of a hydroxylated N-methyl levorphanol were excreted in bile. Thus a remarkable stereoselectivity occurs in the metabolism of these quaternary ammonium compounds in the rat liver.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200220403
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  • 5
    Electronic Resource
    Electronic Resource
    Atmospheric pressure ionization mass spectrometry: The routine determination of 2,4,5-trichlorophenoxyacetic acid and its metabolitesPresented in part at the 8th International Conference on Mass Spectrometry, Oslo, Norway (1979). (1981)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 8 (1981), S. 539-545 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This study demonstrated the utility of negative ion atomospheric pressure ionization mass spectrometry for the routine quantitation of 2,4,5-trichlorophenoxyacetric acid and its glycine and taurine amide metabolites in mouse blood, urine and feces samples. The quantitation of 2,4,5-trichlorophenoxyacetic acid in blood follows a short cleanup procedure and used 2,4,5-trichlorophenoxy-13C6-acetic acid as the stable label isotope diluent. A more extensive cleanup procedure utilizing high-pressure liquid chromatography was required for the determination of 2,4,5-trichlorophenoxyacetic acid and its two metabolites in urine and feces. The glycine amide metabolite was quantitated by the 13C stable label isotope diluent method. The taurine amide relied on an initial separation step followed by using a second 2,4,5-trichlorophenoxy-13C6-acetic acid spike for its isotope diluent. Alkaline hydrolysis of the metabolites, followed by methylation, allowed the methyl ester of 2,4,5-trichlorophenoxyacetic acid to be solely used as the analyte in the negative ion atmospheric pressure ionization mass spectrometry quantitation step.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200081104
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  • 6
    Electronic Resource
    Electronic Resource
    Determination of kerosene and light oil components in blood (1991)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 20 (1991), S. 493-497 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A sensitive and rapid method to analyse fuel components in blood from rats exposed to kerosene or light oil vapour was developed by making use of capillary gas chromatography/mass spectrometry. The aliphatic hydrocarbons with carbon numbers 8-10 and aromatics such as toluene, xylene, 3- and 4-ethyltoluene and trimethylbenzenes were clearly detected in blood from rats exposed to kerosene or light oil vapour, using the head-space method combined with the salting-out technique. The concentration ratio of pseudocumene to toluene in blood exposed to light oil was higher than that in the case of exposure to kerosene. The lower limits of detection were 50 pg and 1 ng in toluene and pseudocumene, respectively. Our suggestion is that this method is useful in forensic investigations to detect fuel components in blood and for the purposes of differentiating kerosene and light oil in blood tissues.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200200810
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  • 7
    Electronic Resource
    Electronic Resource
    The use of tandem mass spectrometry as a problem-solving tool in the industrial environment (1990)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 4 (1990), S. 454-460 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: This paper deals with a number of the benefits associated with a variety of tandem mass spectrometer geometries and the way in which these configurations have been applied to the solution of real problems. It discusses the use made of a variety of tandem mass spectrometry approaches to the study of analytical problems of industrial relevance. ICIs utilization of tandem mass spectrometry has grown substantially from an initial involvement in the early 1980s to a point where a number of instruments have been installed and used predominantly for trace analysis, structural studies and in the characterization of complex mixtures. We have selected a small number of examples of the use of the various tandem mass spectrometry approaches emphasizing the unique features of the technique.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290041025
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  • 8
    Electronic Resource
    Electronic Resource
    Photoelectret state in poly(vinylcarbazole) (1977)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 15 (1977), S. 379-384 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The photoelectret charge in the aluminum-poly(vinylcarbazole) (PVK) conducting-glass (NESA), sandwich cell configuration has been observed to decrease with voltage above some critical voltage, depending on the intensity of illumination. This critical voltage corresponds to the value at which a time-independent photocurrent is observed and also to the “knee-point” voltage in the current voltage plot. The results are explained on the basis of field-assisted detrapping setting in at high field.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1977.180150216
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  • 9
    Electronic Resource
    Electronic Resource
    Synthesis of polymers containing pyridinium ylide and iminopyridinium ylide structure (1983)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 3597-3600 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1983.170211220
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  • 10
    Electronic Resource
    Electronic Resource
    Effect of structure on properties of polypyromellitimide films (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1487-1494 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polypyromellitimides were prepared by the reaction of di(4-aminophenyl) ether (E)/di (4-aminophenyl) methane (M), and pyromellitic dianhydride in dimethylformamide, followed by thermal cyclization in a nitrogen atmosphere. Copolyimides were obtained by taking different molar ratios of diamines in the initial monomer feed. Differential scanning calorimetric, thermogravimetric analysis, and thermally stimulated current studies were carried out on these samples. It was concluded that the dielectric relaxation in these copolymers is due to trapping of the charge carriers. The dielectric relaxation parameters and activation energies were also calculated.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.170220627
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