[Weight distribution and optical characteristics of soil humic acids fractionated by gel chromatography and electrophoresis].

Combination of gel chromatography on Sephadex and polyacrylamide gel electrophoresis was used to obtain molecular weight- and electrophoretic mobility-uniform fractions of humic acids from soil of different types (chernozem, sod-podzol, grey forest, and red soils). Extinction and color (E4/E6) coefficients, as well as weight distribution (%) were studied for all humic acids and their fractions. The fractions differed by the weight distribution (%). Sod-podzol and red soils had twice the amount of high-molecular and half the amount of low molecular HA fractions as compared to chernozem and grey forest soil.