Pyrolysis derivatization of humic substances.2. Pyrolysis of soil humic acids in the presence of tetramethylammonium hydroxide (TMAH)

Abstract

Humic Acids (HAS) extracted from soils of very different origin have been analyzed by pyrolysis in the presence of tetramethylammonium hydroxide. The thermal degradation products consisted mainly of aliphatic series such as fatty acids methyl esters and a,w-methoxy fatty acid methyl esters. Triterpenoid compounds with ursane, oleanane and hopane skeletons were also detected in several samples. Aromatic units derived from lignin moieties were also detected although in minor amounts and corresponded mainly to guaiacyl and syringyl units. This procedure seems to release the more labile. aliphatic moieties attached to the aromatic nuclei of the HA structure.