Possibility of the silylation technique in gas liquid chromatography of fulvic and humic acids

Abstract

The silylation technique was applied to produce volatile and thermally stable tri-methyl (TMS) derivatives suitable for gas liquid chromatography of fulvic and humic acid extracted from a Greenville loam. The chromatograms appeared to be useful for fingerprinting the different organic matter preparations. They had two distinct regions, a region between 0–15 min retention time consisting of a group of peaks due to low molecular weight organic components and another region between 29–45 min retention time consisting of a group of peaks due to higher molecular weight components. The hot water extract was identified with infrared as a polysaccharide, possessing a gas-chromatogram dominated by the low molecular weight components. The HCl extract was similar, but had in addition somewhat more higher molecular weight components. Fulvic acid had both low and high molecular weight components represented in the gas-chromatograms but had a polysaccharide infrared spectrogram. Humic acid chromatograms were dominated by high molecular components, although some low molecular weight peaks were noted. One particular HCl- and/or H 2O polysachharide component seemed to prevail in fulvic as well as in humic acid. There is some evidence that different pretreatments might cause a change in the nature and number of components extracted.