GLYCOSYL LINKAGE ANALYSIS OF WATER SOLUBLE & INSOLUBLE LINKED GLUCANS

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The sample was permethylated and analyzed by MALDI-MS using a 2,5-dihydroxybenzoic acid matrix. Methylation of the sample was accomplished using NaOH/methyliodide. MALDI-TOF-MS was performed with an HP LDI 1700XP mass spectrometer operated in the positive ion mode at 30 kV and with a pressure of 6 x 10-7 Torr. The mass spectrometer was calibrated with a mixture of glucose oligomers (degree of polymerization between 3 and 20). Aqueous solutions of samples were diluted 13 with aqueous 50% acetonitrile containing 100 mM 2,5-dihydroxybenzoic acid, and a portion (0.5 (L) was applied to the probe tip of the mass spectrometer. Samples were desorbed from the probe tip with a nitrogen laser ((=337 nm) having a pulse width of 3 ns and delivering approximately 16 (J of energy/laser pulse.