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  • 1
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 6 (1979), S. 242-248 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chemical ionization spectra of permethylated aldohexopyranosyl-(1-x)-aldohexoses (x = 1-6) with methane, isobutane, methanol and ammmonia as the reagent gases were studied. The chemical ionization methane spectra showed more pronounced differences related to different glycosidic linkages than the corresponding electron impact spectra. In contrast to the electron impact spectra, a reliable differentiation between (1-2) and (1-4) linked disaccharides could be achieved as well as a more detailed characterization of the stereoisomers in case of the (1-4) and (1-6) linked disaccharides. The chemical ionization isobutane spectra showed somewhat higher abundances for the [M+H]+ ions than with methane. It also methane. It also allows an easy differentiation of the various glycosidic linkages but its capability with respect to the discrimination of stereoisomers is inferior to that of methane. The base peak in chemical ionization ammonia spectra is [M+NH4]+, but the spectra are less characteristic than the above, although discrimination of the glycosidic linkages remains possible. Mass analysed ion kinetic energy and collisional activation spectra of selected ions of the chemical ionization spectra showed no characteristic differences, which excludes the possibility of using them as a means of differentiation for these compounds.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 7 (1980), S. 122-126 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In this paper the structure of the most important fragment ion ([C5H9O2]+, m/z 101) in the spectra of permethylated saccharides is investigated. The participation of the C-1 carbon atom in the formation of this ion has been quantitatively determined from the spectra of 13C labelled permethylated glucofuranosides. Investigation of the metastable ion and collisional activation spectra of m/z 101 yielded evidence for an acyclic ion structure.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 7 (1980), S. 127-131 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Collisional activation spectra of quasimolecular ions generated by chemical ionization can be used for the discrimination of stereoisomeric permethylated disaccharides. The best results have been obtained by using ammonia and trimethylamine as reagent gases. In the case of trimethylamine the presence of water seems to play an important role in order to obtain distinctive collisional activation spectra. The structural information obtained with the chemical ionization gases mentioned is complementary. A flow chart is presented for the identification of an unknown permethylated disaccharide.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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