DETERMINATION OF INTERGLYCOSIDIC LINKAGES IN DISACCHARIDES BY HIGH-PERFORMANCE TANDEM MASS-SPECTROMETRY

High performance tandem mass spectrometry employing a four-sector instrument is used for the characterization of disaccharides. In contrast to low energy collisions, high energy collision induced dissociation (CID) of B2 sequence ions (C(1)-carbenium ions) derived from trideuterioacetylated dihexopyranosides permits immediate differentiation of all four linkage types (1-2, 1-3, 1-4 and 1-6) irrespective of the nature of the monosaccharide subunits. Moreover, high energy collisions produce spectra richer in features in that less energy-demanding processes (loss of peripheral residues such as AcOH-d3, Ac2O-d6 and ketene-d2) are supplemented by characteristic charge-remote fragmentations (radical eliminations, cleavages within the sugar rings). In some cases, assignment of the anomeric configuration (α/β) of the interglycosidic linkages (requiring difficult conditions in low energy CID) is also possible. © 1990.