Amphiphilic properties of humic substances in soils of the southern Vitim Plateau (Transbaikalia, Eastern Siberia)

Abstract Humic substances of soils are considered as a multicomponent system of amphiphilic (exhibiting both hydrophilic and hydrophobic properties) substances. Humic substances from soils of different genesis in the south of the Vitim Plateau (quasigley chernozem – Turbic Chernozem Molliglossic and brown soil – Stagnic Phaeozem Molliglossic) were studied. Using the hydrophobic interaction chromatography on Octyl-Sepharose® CL-4B, we separated a mixture of humic (HAs) and fulvic acids (FAs) due to their different ability to enter into hydrophobic interactions with the gel matrix. A higher percentage of hydrophobic compounds was revealed in HAs of quasigley chernozem, compared to HAs of brown soils, and FAs. The fulvic acid sample showed a lower capacity for hydrophobic interactions than the humic acid sample.