We have developed a concise tool for the investigation of the transition of humic substances in environmental water. The separation of water-soluble humic substances was achieved rapidly and effectively by capillary electrophoresis using a polyacrylamide-coated capillary and a phosphate electrophoretic buffer solution (pH 7.0) containing hydroxyethyl cellulose. The separation mechanism was assessed using the ultrafiltration technique. The effect of the complexation of humic substances with metal ions was studied by using the proposed method. When Fe(III) ions or EDTA was added to the sample solution of fulvic acid, a distinct change in the electropherogram pattern based on the conformational change of fulvic acid was observed. The successful application of the proposed method to the characterization of humic substances in a river water sample was also demonstrated.

A simple, rapid, and precise dynamic coating capillary electrophoretic separation method for water-soluble humic substances is proposed. An aqueous solution containing hydroxyethyl cellulose (HEC), polyethylene glycol (PEG), and pH buffer component was employed for both the dynamic coating agent and the separation medium. The procedure for the coating of the capillary inner wall was simply filling the buffered polymer mixture solution into the capillary that had been treated with 1 M aqueous HC1 solution. The solution for the capillary coating was directly used as the electrophoretic buffer solution for CE separation. Excellent performance for the separation of humic acid was obtained using the solution containing 0.5% (w/v) HEC, 1.0% (w/v) PEG 10000, and 0.1% (w/v) PEG 8000000. Excellent reproducibility and durability were obtained even at slightly alkaline conditions at pH levels above 8. The separation of 0.1 - 2 kbp of DNA ladder by the proposed method showed was also achieved

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