Pyrolysis gas chromatography atomic emission detection method for determination of N-containing components of humic and fulvic acids

Abstract

In this study, a pyrolysis gas chromatography/atomic emission detector (pyrolysis GC/AED) analytical system was established and then investigated for its utility in the chemical characterization of the N-containing components of humic and fulvic acids. Our results show that: (1) the optimal sample pyrolysis temperatures, for observing the characteristic profiles of N-containing components in soil organic matter constituents such as humic and fulvic acids, are from 300 to 500 °C; (2) the main N-containing pyrolysis products of humic and fulvic acids are acetonitrile, hydrogen cyanide, ammonia, pyridine, pyrrole and acetamide; (3) except for pyridine, each of the main N-containing fragments had more than one dominant N-containing source, with source structures being different for humic acid and fulvic acid; and (4) pyrolysis GC/AED with high selectivity and sensitivity may be a useful tool for tracking quantitatively the changes of SOM N-containing components during their decomposition in soils.