13C NMR spectroscopy of humic acids of different origin

The fragment composition of humic acids was studied by quantitative 13C NMR spectroscopy. A comparative analysis of the chemical composition of humic acids extracted from organic matter of different origin was performed. A number of structural parameters determined from the 13C NMR spectra was proposed for the classification of humic acids by origin. © 2003 by MAIK "Nauka /Interperiodica" (Russia).