Capillary zone electrophoresis for the determination of light-absorbing anions in environmental samples

A rapid and simple method for separation and determination of inorganic anions by capillary zone electrophoresis was described. The detection was carried out directly with a diode array detector. The experimental conditions, such as concentration of carrier electrolyte, capillary length, voltage, and temperature were optimized. In order to improve selectivity, different organic modifiers were also investigated. The baseline separation of 10 light-absorbing anions was accomplished within 3.5 min with a background electrolyte consisting of 50 mM sodium tetraborate containing 5% MeOH. Linear plots were obtained in the concentration range of 0.1–10 μg/ml. With sample stacking injection, the quantitation limits of the anions were found to be in the range of 0.02–0.1 μg/ml. The proposed method was successfully applied to the determination of inorganic anions in environmental samples and in effluents of a power plant.