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Comparison between analytical pyrolysis and nitrobenzene oxidation for determination of syringyl/guaiacyl ratio in Eucalyptus spp. lignin

2008; North Carolina State University; Volume: 3; Issue: 3 Linguagem: Inglês

10.15376/biores.3.3.701-712

1930-2126

Cláudio F. Lima, Luiz C. A. Barbosa, Cristiana Resende Marcelo, Flaviano Oliveira Silvério, Jorge Luiz Colodette,

Enzyme-mediated dye degradation

Pyrolysis-gas chromatography/mass spectrometry (Py-GC-MS) was applied to measure the lignin syringyl/guaiacyl (S/G) ratio in E. dunni, E. grandis, E. nitens, E. urograndis, and E. urophylla woods. A total of 41 compounds were identified, of which 11 were derived from carbohydrates and 30 from lignins. The S/G ratio was calculated on the basis of the areas of peaks recorded in the pyrograms and compared with the results obtained by alkaline nitrobenzene oxidation. The values of S/G found by pyrolysis were similar for all the species using the compounds guaiacol, 4-methylguaiacol, 4-vinylguaiacol, vanillin, 4-ethylsyringol, 4-vinylsyringol, homosyringaldehyde, acetosyringone, and syringylacetone, as lignin markers. The selected markers were efficient for the deter-mination of S/G ratio in eucalyptus wood by Py-GC-MS. The Py-GC-MS technique produced results that are comparable to the nitrobenzene oxidation method, with the advantage of requiring small wood samples and a short analysis time.