Determination of interglycosidic linkages in disaccharides by high performance tandem mass spectrometry

Abstract

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 B 2 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- d 3, Ac 2O- d 6 and ketene- d 2) 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.