Pyrolysis-gas chromatography/Mass spectrometry analysis of phenolic and etherified units in natural and industrial lignins

✍ Scribed by Susana Camarero; Paola Bocchini; Guido C. Galletti; Angel T. Martínez

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 94 KB
• Volume: 13
• Category: Article
• ISSN: 0951-4198
• DOI: 10.1002/(sici)1097-0231(19990415)13:7<630::aid-rcm535>3.0.co;2-5

✦ Synopsis

Milled-wood lignin (MWL) from Carpinus betulus, Eucryphia cordifolia, Picea abies, Pinus sp. and Bambusa sp., Kraft lignin from Fagus sylvatica and Eucalyptus globulus, and alkali lignin and hemicellulose-linked lignin from Triticum aestivum, were investigated with respect to their composition in phenolic and etherified phenylpropanoid H (p-hydroxyphenyl), G (guaiacyl) and S (syringyl) units. For this purpose, a methodology based on lignin permethylation, followed by pyrolysis-gas chromatography/mass spectrometry, and quantitation of marker compounds (H-, G-and S-type vinylphenols and their methylated derivatives) in single-ion chromatograms, was developed. The phenolic content in the samples analyzed ranged from 2% of total units in hemicellulose-linked lignin to near 70% in Kraft lignins. Softwood MWL showed higher amounts of phenolic units than MWL from annual plants and hardwoods. It was found that the phenolic content of MWL from the Austral tree species E. cordifolia was unexpectedly high for a hardwood lignin. The significance of this finding in terms of lignin degradability by white-rot fungi, of biotechnological interest, is discussed.