Structural analysis of the neuraminic acid linkages in deaminated trisaccharide-alditols by gas-liquid chromatography-mass spectrometry

Abstract

The separation and structural analysis of four deaminated sialotrisaccharide alditols as their permethyl ethers by gas-liquid chromatography (g.l.c.) and gas-liquid chromatography-mass spectrometry (g.l.c.-m.s.) is described. For the assignment of (2→3) and (2→6) linkages between sialic acid and d-galactose, trisaccharides having two different kinds of alditol units and also isotopic labelling of the sialic acid moiety have been used. The analysis by m.s. of the sialic acid moiety liberated is also presented. It is shown that the alditols may be separated from one another by g.l.c. with the SE-30 stationary phase. The position of the terminal glycosidic linkage may be established by m.s., without deuterium labelling of the molecule, in a similar way to that described for the corresponding alditols composed of simple hexoses. The use of g.l.c.-m.s. in studies of oligosaccharide mixtures produced by N-deacetylation and deamination of sialic acid-containing glycopeptides is discussed.