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Identifying acetylated lignin units in non‐wood fibers using pyrolysis‐gas chromatography/mass spectrometry
Author(s) -
del Río José C.,
Gutiérrez Ana,
Martínez Ángel T.
Publication year - 2004
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.1457
Subject(s) - chemistry , pyrolysis–gas chromatography–mass spectrometry , lignin , mass spectrometry , pyrolysis , acetylation , chromatography , gas chromatography , gas chromatography–mass spectrometry , organic chemistry , biochemistry , gene
Abstract A series of non‐wood plant fibers, namely kenaf, jute, sisal and abaca, have been analyzed upon pyrolysis‐gas chromatography/mass spectrometry (Py‐GC/MS) of the whole material. The pyrolysis products mainly arise from the carbohydrate and lignin moieties of the fibers. The lignin‐derived phenols belonged to the p ‐hydroxyphenylpropanoid (H), guaiacylpropanoid (G) and syringylpropanoid (S) structures, and showed a high S/G ratio of between 2.0 and 5.4, the highest corresponding to kenaf. Among the lignin‐derived phenols released, small amounts of sinapyl and coniferyl acetates (in both cis ‐ and trans ‐forms) were identified for the first time upon Py‐GC/MS of lignocellulosic materials. Acetylation of the sinapyl and coniferyl alcohols was at the γ ‐position of the side chain. The release of these alcohols derived from intact acetylated lignin units upon pyrolysis seems to indicate that the native lignin in the fibers selected for this study is at least partially acetylated. Sinapyl (and coniferyl) acetates have recently been suggested to be authentic lignin precursors involved in the polymerization of lignin along with the normal sinapyl and coniferyl alcohols. Py‐GC/MS will offer a convenient and rapid tool for analyzing naturally acetylated lignins, as well as to screen plant materials for the presence of acetylated units in lignin. Copyright © 2004 John Wiley & Sons, Ltd.