A gas-to-solid phase methanolysis method for the analysis of small amounts of oligosaccharides

A gas-to-solid phase methanolysis method for the analysis of oligosaccharides is presented. The advantages of using this new gas-to-solid phase method, as opposed to conventional bulk phase techniques, are described, along with comparisons of results obtained from both techniques. The reliable bulk phase methanolysis methods are used as benchmarks for assessing the extent of completion of the gas-to-solid reactions. Gas chromatographic - mass spectrometric (GC-MS) data show that, in general, higher temperatures and longer reaction times are required for completion of the gas-to-solid methanolysis process than for completion of the bulk phase reaction. On the other hand, the gas-to-solid procedure requires only minimal amounts of substrate that would be difficult to characterize using bulk phase methanolysis due to losses during clean-up procedures. Gas-to-solid methanolysis reactions of permethylated di- and trisaccharides were investigated (GC-FID and GC-MS), following initial experiments performed in order to characterize the GC retention times and mass spectra of permethylated standard monosaccharides. Conversion of neutral disaccharides, as well as neutral and acidic trisaccharides, to their respective monosaccharides was successful using the gas-to-solid method. The GC-FID and GC-MS traces show that the gas-to-solid method gives a cleaner reaction than the bulk phase method.