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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 9 (1995), S. 809-814 
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The aim of this article was to study the influence of different matrix molecules on the quality of matrix-assisted laser desorption/ionization mass spectra of oligosaccharides. An important criterion was the sample preparation, i.e. the crystallization process leading to the matrix from which the analytes were desorbed and investigated. Quality criteria were, among others, the resulting molecular peak intensity, the mass resolution, and the suppression of unwanted matrix peaks. It was found that a mixture of 2,5-dihydroxy benzoic acid (DHB) and 1-hydroxy isoquinoline (HIC) in a weight ratio of 3:1 was best suited for the analytical investigation of oligosaccharides. In addition, this matrix mixture was found to be quite tolerant against all kinds of buffers, salts, and even additives such as sodium dodecyl sulfate (SDS). Furthermore, we determined the different affinities of the alkaline metals to the carbohydrates and found that cesium and potassium ions ionize oligosaccharides about three times better than sodium ions and therefore have an important influence on the quantum yield.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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  • 2
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: A Nafion membrane was tested as a new tool for a fast and easy sample pretreatment for matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) measurements. This membrane material was used for ion exchange and carbohydrate purification with minimal quantities of sample solution. An ion exchange method for carbohydrates was developed and demonstrated on a Dextran sample. The cations of the original sample were replaced within minutes by potassium or cesium ions. Another feature of this membrane was the fact that proteins and peptides adsorb on the acid surface. This behavior was investigated as a purification step for carbohydrates with high peptide and protein impurity concentrations. It was found that oligosaccharide libraries from rat- and mouse IgG mass spectra can be obtained clearly in the presence of high peptide impurities.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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