Separation of Humic Acid Constituents by Polyacrylamide Gel Electrophoresis in the Presence of Concentrated Urea Using a Preparative Electrophoresis System

摘要

To separate humic acids (HAs) into their constituents,polyacrylamide gel electrophoresis (PAGE) was carried out in the presence of 7 M urea using a preparative electrophoresis system.Upon PAGE,the dark-colored constituents of HAs were separated by their molecular sizes and recovered by precipitation with acid.Considerable parts of the fluorescent constituents of HAs with the lowest molecular size were rendered soluble in acid and the acid soluble fluorescent constituents were recovered by adsorption onto DAX-8 resin.However,the colorless constituents of HAs were lost during the electrophoresis.These constituents were considered as the low molecular size constituents separated due to disruption of the hydrogen bonding and hydrophobic interaction by 7 M urea.The measurement of diffuse reflection infrared Fourier transform spectra indicated that the chemical properties of HA constituents were different from each other.The results show that preparative PAGE in the presence of concentrated urea is a useful method for fractionating and collecting the constituents of HAs.