Pedosphere 6(2): 97--106, 1996
ISSN 1002-0160/CN 32-1315/P
©1996 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Study on nitrogen forms in phenolic polymers incorporating protein by 15N CP-MAS NMR |
| CHENG Li-Li and WEN Qi-Xiao |
| Institute of Soil Science, Academia Sinica, P. O. Box 821, Nanjing 210008 (China) |
| ABSTRACT |
| Phenolic polymers synthesized by reactions of p-benzoquinone with 15N-labelled protein or (15NH4)2SO4 were studied by using 15N CP-MAS NMR technique in combination with chemical approaches. Results showed that more than 80% of nitrogen in quinone-protein polymers was in the form of amide with some present as aromatic and/or aliphatic amine and less than 10% of nitrogen occurred as heterocyclic N. The nitrogen distribution in the non-hydrolyzable residue of the quinone-protein polymers was basically similar to that of soil humic acid reported in literature with the exception that a higher proportion of N as heterocyclic N and aromatic amine and a lower proportion of N as amide and aliphatic amine were found in the former than in the latter. More than 70% of total nitrogen in quinone-(NH4)2SO4 polymer was acid resistant, of which about 53% occurred as pyrrole, nitrile and imino type N. The possible roles of the reactions of phenols or quinones with proteins in the formation of humic acid, especially the non-hydrolyzable nitrogen in humic acid, are discussed. |
| Key Words: humic acid, 15N NMR, phenolic polymer |
| Citation: Cheng, L. L. and Wen, Q. X. 1996. Study on nitrogen forms in phenolic polymers incorporating protein by 15N CP-MAS NMR. Pedosphere. 6(2): 97-106. |
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