prepared according to the Bj0rkman procedure gift from Dr. K. Haider, F.A.L., Braunschweig, GFR
suspension in methanol; 10 yg standard
remarks - The pyrolysis mass spectra of lignins are characterized by the presence of pyrolysis products derived from each of the main phenolic building blocks. In the case of grass lignins these are the parahydroxybenzoic, quaiacylic and syringylic acid moieties, giving rise to three discrete series of phenolic signals, namely m/z 94, 108, 120, 134, m/z 124, 138, 150, 164 and m/z 154, 168, 180, 194 respectively (signals beyond m/z 160 not shown). As confirmed by the Py-GC-MS studies of Bracewell et at. (ref. 186), the syringylic acid series is particularly prominent in hardwood lignins (e.g. beech lignin) but absent in softwood lignins (e.g. Douglas fir lignin). See also Part I, Section 3.6.
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