Glucosamine and Galactosamine Distribution in a Soil as Determined by Gas Liquid Chromatography of Soil Hydrolysates: Effect of Acid Strength and Cations

Abstract

Abstract The objectives of this study were to determine the distribution of glucosamine and galactosamine in an Orthic Humic Gleysol and to investigate the effects of acid strength and cations on amino sugar yields. Wet sieving was used to fractionate the soil into a water‐soluble fraction and fraction of different particle sizes. All fractions were hydrolyzed with 3 N and 6 N HCl. Glucosamine and galactosamine were quantified by GLC of their alditol acetates. Amino sugars were determined in all fractions, but only trace amounts were detected in the water‐soluble fraction. A definite parallel was found between C, N, and amino sugars. The highest yields of amino sugars were obtained with 6 N HCl in all fractions except the clay fraction, where identical yields were obtained with 3 N and 6 N HCl. The largest difference in yields (100%) between the two treatments was observed in soil fractions containing plant residuces, whereas only a 25% difference was obtained in the major plant‐free fraction. These results indicate that the amino sugar‐containing macromolecules in soil fractions composed of well‐humidified material are more easily hydrolyzed than the corresponding polymers in plant residue fractions. Removal of cations, such as Fe, during derivatization of the sugar hydrochloride resulted in a 40% increase in amino sugar yield. Direct analyses of amino sugars on an amino acid analyzer gave comparable results but was more time consuming.