Abstract
Curie-point pyrolysis-gas chromatography-mass spectrometry has been used to chemically characterize fulvic acid, humic acid, hymatomelanic acid and polysaccharide fractions of a representative soil. A detailed study of all the pyrolysis products was made. By comparing the results of this study with previous pyrolysis data for lignins, degraded lignins, polysaccharides, proteins, etc., we have been able to obtain more detailed information about the chemical composition of the pyrolysis products from different soil organic matter fractions. It is shown that fulvic acid fractions consist mainly of polysaccharide and/or carbohydrates and polyphenols, that humic acid and humin fractions are complex mixtures of several biopolymers such as polysaccharides, partially degraded lignins, peptides and lipids and that the hymatomelanic acid fraction represents mainly lipid materials.