Nuclear magnetic resonance humic substance analysis

In order to investigate the properties of individual fractions of humic substances, various modes of high performance liquid chromatography (HPLC) have been employed. Hydrophobic interaction chromatography (5) has proved to be an effective separation technique, resulting in five distinct humic fractions from one sample. Structural analysis of these fractions was subsequently performed by infrared and nuclear magnetic resonance spectroscopy, and molecular weight distribution was also measured. 

M.A. Wilson, A.H. Gillam, P. Collin (1983). Analysis of the structure of dissolved marine humic substances and their phytoplanktonic precursors by H and C nuclear magnetic resonance. Chem. Geoi, 40,187-201. 

Analysis of the degradation products obtained from pyrolysis and oxidative degradation studies suggests that terrestrial humic substances are highly aromatic (c.70% of total C). However, these techniques tend to overemphasize the importance of aromatic and phenolic units. Non-degradative techniques, such as 1H and 13C nuclear magnetic resonance, probably give more realistic aromatic carbon contents of 20—50% for soil humics,... 

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