ANALYSIS OF BEECH WOOD SAMPLES, ITS MILLED WOOD LIGNIN AND POLYSACCHARIDE FRACTIONS BY CURIE-POINT AND PLATINUM FILAMENT PYROLYSIS MASS-SPECTROMETRY

Beech wood samples (stem, root and biodegraded wood) as well as beech milled wood lignin, beech polysaccharide fractions (holocellulose, xylan and technical xylan) and microcrystalline cellulose were analysed by pyrolysis-mass spectrometry (Py-MS), i.e. Curie-point pyrolysis low voltage electron impact (EI) MS, as well as by in-ion source platinum filament pyrolysis MS under both ammonia chemical ionisation (CI) and low voltage EI conditions. The mass spectra reveal the presence of monomeric, submonomeric as well as di- and oligomeric pyrolysis products from polysaccharides and/or lignin. The difference in pyrolytic behavior of polysaccharides in the complex wood matrix and of the purified polysaccharides may find its cause in chemical and physical interactions between polysaccharides and lignins in the wood, or may be due to the presence of considerable amounts of inorganic cations in the sample. The pyrolytic behavior of lignin is not significantly influenced by the presence of inorganic cations. The holocellulose and xylan data also exhibit chlorinated lignin marker compounds, which point to the presence of partly chlorinated lignin in the sample. This is probably an artefact due to the isolation procedure of these fractions, which involves treatment with sodium hypochlorite solution. The CI data of the technical xylan fraction indicate the presence of di- and oligomeric pentoses, hexoses and pentose/hexose sugars. These are probably formed during the isolation procedure (which involves extraction of wood chips at 170°C) by partial depolymerisation of the polysaccharide moiety. © 1990.