Thermal depolymerization analysis of neutral polysaccharides

Polysaccharide analysis requires identification of monomeric units, sequence, linkage position and anomeric configuration. Conventional analysis is very tedious requiring release of monomeric units by chemical or enzymatic hydrolysis followed by derivatization to volatile species prior to gas chromatographic analysis. An alternative approach is thermal fragmentation which results in the formation of 1,6-anhydro-monosaccharides and 1,6-anhydro-oligosaccharides. The presence of the anhydro monomers relates information about the composition of monomeric isomers, the intact anhydro dimers provide information about linkage type and anomeric configuration. In this study, various neutral polysaccharides were analysed by off-line pyrolytic techniques, the pyrolysates were analysed by trimethylsilylation-gas chromatography and per-O-benzoylation high performance liquid chromatography. Pyrolysate identification was performed by comparison with retention times of standards as well as confirmation by mass spectrometry in both chemical ionization and electron impact modes.