Electrochemical behaviors of ascorbic acid and uric acid in micellar aqueous and their selective determination

The electrochemical behaviors of ascorbic acid (AA) and uric acid (UA) in micellar aqueous solutions have been studied by cyclic voltammetry at glassy carbon electrode. The experimental results show that the anodic peak current of AA and UA in the cetylpyrid bromide (CPB) aqueous solutions, while, it decreases in the sodium dodecyl benzene sulfonate (SDBS) aqueous solutions. The anodic peak potential of AA and UA shift more negative in CPB aqueous solutions, while it shifts more positive in SDBS aqueous solutions. The anodic peak of UA can be separated from AA by 270 mV in CPB aqueous solutions. Linear calibration curves were obtained for AA and UA in ranges of 1.0 x 10(-6) similar to 1.0 x 10(-2) mol/L and 5.0 x 10(-7) similar to 1.0 x 10(-3) mol/L respectively in CPB aqueous solutions by differential pulse voltammetry. The detection limit of UA in the presence of 200-fold excess of AA was 5.0 x 10(-6) mol/L. The method has been applied in determining the concentration of UA in human urine with satisfactory results.