Determination of polysaccharide linkage and branching by reductive depolymerization. Gas-liquid chromatography and...

A series of partially methylated anhydro-D-alditol acetates has been prepared and analyzed by g.l.c. and g.l.c.-m.s. The reference compounds were obtained by reductive cleavage of permethylated and partially methylated standard methyl glycosides, and standard di-, tri-, and tetra-saccharides of known composition and linkage. Structural characterization included retention times on g.l.c. using DB-225 capillary columns and mass spectrometry in both the chemical- and electronionization modes. This compiled library allows further evaluation of the applicability of the reductive cleavage procedure for determining linkage or branching (or both) of new and more complex oligosaccharides. The technique has been applied to microgram amounts of a bacterial-membrane oligosaccharide and to a saccharide obtained from the urine of a mannosidosis patient. The procedures are simple, reliable, and applicable to small amounts of isolated biological materials.