Determination of Structural Isomers of Xyloglucan Octasaccharides Using Post-Source Decay Fragment Analysis in MALDI-TOF Mass Spectrometry.

Abstract Post-source decay (PSD) fragment analyses by MALDI-TOFMS were applied to the characterization of two analogous structure isomers of xyloglucan octasaccharides (XXLGol and XLXGol) from Tamarind seed. Almost all possible fragment ions were detected by a mutli-site cleavage at the glycosidic linkages. The same fragment ions were observed in their spectra, but the relative intensities of some of the ions differed greatly. The detailed investigation of the relative intensities of the fragment ions enabled definitely to distinguish the analogous structure isomers of the highly branched octasaccharides.