Some Aspects on SIMON'S Fractionation of Humic acid

Abstract

Humic acids extracted with sodium hydroxide solution were almost insoluble to SIMON'S pH 4 acetate buffer, while humic acids soluble to SIMON'S pH 4 acetate buffer were obtained when neutral sodium pyrophosphate solution were used for extraction. And the pH 4 insoluble humic acids were changed to the pH 4 soluble acids by the treatment with neutral sodium pyrophosphate solution; and the pH 4 soluble humic acids were changed to pH 4 insoluble from by the addition of ferrous or aluminium ion in sodium hydroxide solution. So it was recognized that humic acids combined with iron or aluminium ion were insoluble to SIMON'S pH 4 acetate buffer, and humic acids not combined with these metal ions were soluble to SIMON'S pH 4 acetate buffer.