prepared according to the Brauns procedure gift of Dr. K. Haider, F.A.L., Braunschweig, GFR
suspension in methanol; 10 yg standard
remarks - Comparison of this spectrum with that of Bj^rkman lignin (Spectrum E.9) shows the strong influence of the preparation procedure on composition and structure of the lignin obtained. This reflects a basic problem in obtaining pure, undegraded lignin samples as the lignin moieties in plant matter are intricately connected to the hemicellulose fraction (ref. 85). As shown in the spectrum of Douglas fir (Spectrum E.ll), however, characteristic lignin patterns are easily obtained from whole wood samples by Py-MS. This should enable fast characterization of lignins without lengthy and risky separation procedures as well as provide a practical guide to comparing the effectiveness and reliability of various extraction and separation techniques for lignins.
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