A new technique of carbohydrate analysis using post-source decay fragmentation by MALDI-TOFMS

Structural analyses of carbohydrates were performed by a new technique usin g MALDI-TOF mass spectrometry. Sequential fragment ions were observed in al e post-source decay (PSD) fragment spectra of MALDI-TOFMS, which are like t he MS/MS fragment spectra. These fragment ions were produced by cleavages o f the glycosidic linkages. The structural isomers of sugar-branched cyclode xtrin derivatives were distinguished by a relative ion intensity analysis. The fragment ions produced by one-site cleavage of the glycosidic linkage h ad a much higher intensity than that produced by two-site cleavage. In addi tion, the glycosidic linkage of alpha 1-4 cleaved more easily than that of alpha 1-6 in MALDI-PSD fragmentation. These results strongly indicated that the relative ion intensity analyses of these MALDI-PSD fragment ions enabl e us to distinguish structural isomers and to perform a linkage analysis.