Humic acid isolated from IHSS peat was fractionated using a combination of organic and aqueous solvents into three individual fractions, a non-amphiphilic humic-like material, an amphiphilic humic-like and lipid fractions, and one amphiphilic-lipid composite material. The whole humic acid as well as its fractions were radiocarbon dated. Considerable differences in the ages of these fractions were found.  Correlations between the radiocarbon age and molecular properties of these fractions were studied. Properties such as carbon-type distribution and hydrophobic to hydrophilic carbon ratio determined from 13C solid state NMR, contribution of labile fractions determined by differential scanning calorimetry, amphiphilicity determined by surface tension measurements as well as the microbial degradation were determined for all the samples. Implications of the findings on the understanding of the dynamics of organic matter in the soil are discussed.

Molecular properties and radiocarbon age of humic acid and its fractions

243rd National Meeting (2012)

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