Linkage position determination in a novel set of permethylated neutral trisaccharides by collisional‐induced dissociation and tandem mass spectrometry
A set of neutral permethylated trisaccharides identical in the non‐reducing (A → B) disaccharide and linkage isomeric in the reducing terminal (B → C) disaccharide has been synthesized. Collision‐activated tandem mass spectrometry was used for analysis of the B → C linkage position. The trisaccharides, gal(β1 → 4)glc(β1 → X)glc, where X = 3, 4 and 6, were synthesized and examined using fast atom bombardment collision‐induced dissociation tandem mass spectrometry. Results were rationalized using molecular modeling. We have previously reported results for determination of the A → B linkage position with isomeric sets of synthetic trisaccharides containing internal amino sugars. The neutral trisaccharides were synthesized to isolate electronic effects of the amino group. An approach of relating daughter ion to parent ion ratios and collision energy offset was used to generate slopes that predict linkage position in glc β1 → X glc reducing end glycoside form of terminal trisaccharides. Copyright © 1992 John Wiley & Sons, Ltd.