Characterization of within-tree variation of lignin components in Eucalyptus camaldulensis by pyrolysis-gas chromatography

Pyrolysis-gas chromatography (Py-GC) using a vertical microfurnace pyrolyzer was applied to the precise determination of the 'within-tree variation' of the ratio of syringyl and guaiacyl units (SIG ratio) for lignin in Eucalyptus camaldulensis. On the pyrogram of the Eucalyptus obtained at 450 degrees C, many characteristic peaks derived from syringyl and guaiacyl units of lignin were reproducibly observed, together with those from cellulose and hemicellulose. On the basis of the relative intensities of those characteristic peaks relating to the syringyl and guaiacyl units, the 'within-tree variation' of the SIG ratio was determined precisely in about 1 h using only about 0.1 mg of the powdered wood sample with a 2% relative standard deviation. The results obtained were also compared with those obtained by the thioacidolysis method.