Oxime-trimethylsilylation method for analysis of wood pyrolysate

Oxime-trimethylsilylation (TMS) method was applied to the analysis of wood pyrolysate. Quantitative determination of hydroxycarbonyls such as glycolaldehyde, which are important pyrolysis products of wood polysaccharide, is difficult as indicated by the gas chromatography–mass spectrometry (GC–MS) and 1H NMR analysis of glycolaldehyde. Glycolaldehyde decomposed into formic acid and the unknown compound with molecular weight of 72 at the injector in its GC analysis. 1H NMR analysis of glycolaldehyde in acetone-d6 indicated the complex mixture with its dimerization products. Glycolaldehyde was quantified precisely as oxime-TMS derivative (E/Z-mixture) of the monomer by GC after oximation with hydroxylamine hydrochloride and the following trimethylsilylation with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA). With this method, the other carbonyls such as furfural, 5-hydroxymethylfurfural and hydroxyacetone could also be determined as their oxime-trimethylsilylated derivatives. Furthermore, anhydrosugars such as levoglucosan and levomannosan in wood pyrolysate were also determined, simultaneously, as their TMS derivatives. Finally, oxime-TMS method is proposed as a quantification method of the pyrolysis products derived from wood polysaccharide.