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Humic Substances Research






The composition of humic acids (HAs) and Fulvic Acids (FAs) from Inogashira (Umbric Andosol) and Dando (Dystric Cambisol) soils authorized as standard samples by the Japanese Humic Substances Society was characterized using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) and X-ray diffraction (XRD) 11 band profile analysis. In FTICR-MS, the number of peaks that molecular formulas were assigned to was 2549-2913 for the FAs and 1943-2457 for the HAs. Molecular formulas with H/C and O/C ratios similar to condensed hydrocarbons were dominant in both the HAs, while those with H/C and O/C ratios similar to lignin were more abundant in the Dando HAs than in the Inogashira HAs. In both the FAs, molecular formulas having H/C and O/C ratios similar to lignin, condensed hydrocarbons, and tannins were dominant. The double bond equivalent (DBE), an index of the degree of unsaturation, was in the range of 0-30. However, larger DBE values of 26-30 were observed only in the Inogashira HAs with a larger degree of humification. The XRD results also showed that the Inogashira HAs contain larger amounts of condensed aromatic structures with a higher condensation degree. Relative content of carbon layer planes estimated from the peak area of the 11 band profile analysis, which could be estimated only for HAs, was 0.48-1.68 nm (4-37 rings) in the Inogashira HAs and 0.48-1.20 nm (4-19 rings) in the Dando HAs.


Copyright © 2012 Japanese Humic Substances Society. All Rights Reserved.

Included with the kind written permission of the copyright holder.


Journal ISSN: 1349-4368

Original Publication Citation

Ikeya, K., Sleighter, R. L., Hatcher, P. G., & Watanabe, A. (2012). Compositional features of Japanese Humic Substances Society standard soil humic and fulvic acids by Fourier transform ion cyclotron resonance mass spectrometry and x-ray diffraction profile analysis. Humic Substances Research, 9, 25-33.


0000-0003-1833-7050 (Sleighter), 0000-0002-1606-1305 (Hatcher)