INFLUENCE OF DIFFERENT GLYCOSIDIC LINKAGES ON RELATIVE ION INTENSITIES IN POST-SOURCE DECAY FRAGMENTATION OF A XYLOGLUCAN HEPTAOLIGOSACCHARIDE USING MATRIX-ASSISTED-LASER-DESORPTION IONIZATION TIME-OF-FLIGHT MASS-SPECTROMETRY/

Post-source decay fragment analysis using matrix-assisted laser desorp tion/ionization time-of-flight mass spectrometry (MALDI-TOFMS) has bee n applied to a highly branched xyloglucan heptasaccharide from tamarin d seed. All fragment ions were produced by cleavage of the glycosidic linkages, including multi-site cleavages. The relative intensities of fragment ions that originated from one-site cleavages of the glycosidi c linkages were much higher than those arising from two-site cleavages of the same kind of glycosidic linkage, which were in turn higher tha n those from three-site cleavages. The types of glycosidic linkages we re an important factor which influenced the relative intensities of th e MALDI-PSD (post-source decay) fragment ions. In the MALDI-PSD fragme nt spectrum of the xyloglucan heptasaccharide, the relative intensitie s of the ions produced by the cleavage of an alpha 1-6 glycosidic link age were much higher than those arising from cleavage of the beta 1-4 glycosidic linkage. (C) 1998 John Wiley & Sons, Ltd.