Structural Investigation of Synthetic Lignins by Matrix-assisted Laser Desorption/Ionization Time-of-flight Mass Spectrometry

✍ Scribed by Francesco De Angelis; Patrizia Fregonese; Franca Verì

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 470 KB
• Volume: 10
• Category: Article
• ISSN: 0951-4198
• DOI: 10.1002/(sici)1097-0231(19960731)10:10<1304::aid-rcm591>3.0.co;2-0

✦ Synopsis

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was used to structurally investigate a synthetic model of lignin, obtained by polymerization of coniferyl alcohol in the presence of horseradish peroxidase and hydrogen peroxide. In contrast to the widespread understanding of lignins as high molecular weight and irregular polymers, repetitive units corresponding to the starting monomer are revealed by the spectra, forming oligomer species with molecular weights in the range of 500-1500 Da. Time-dependent studies of the process have allowed the interpretation that synthetic lignin is formed under thermodynamic control, preferentially via a dehydrogenative polymerization process rather than by an ionic mechanism. During the first stages of the process, higher oligomers are formed which subsequently undergo degradation. Also, dimers and trimers, produced at the beginning of the reaction, have structures that can be interpreted as those of oligolignols already described in the literature.