ABSTRACT

Humic acid and kerogen samples isolated from some Recent sediments of different environments were analyzed by vacuum pyrolysis to characterize their chemical nature. The samples were pyrolysed at 500°C in vacuo (about 10^-2 Torr.). Gravimetric and elemental analyses of the pyrolysis residue indicated that the pyrolytic degradation resulted in the loss of carbon and nitrogen in the range of 35–53% and 53–68%, respectively. The pyrolysate was trapped and extracted with chloroform. It was fractionated using silica gel and Ag⁺-impregnated silica gel column chromatography. Subsequent gas chromatographic analyses enabled quantification of n-alkane and n-alkene homologues. Generated straight-chain hydrocarbons (≥C₁₄) amounted to about 1–4mg per g carbon in the humic acids and to about 2–20mg per g carbon in the kerogens. The potential of the technique to characterize the chemical nature of the humic materials is discussed.