ABSTRACT
The silver doped poly ( L-lysine ) modified glassy carbon electrode was fabricated by cyclic voltammetry, the surface of the electrode was characterized by scanning electron microscopy and electrochemical impedance spectroscopy. The electrochemical behaviors and the simultaneous detection of xanthine and uric acid were studied by cyclic voltammetry and differential pulse voltammetry. The results indicated that this modified electrode exhibited excellent electrocatalytic activity towards the oxidation of xanthine and uric acid. The stable oxidation peaks of xanthine and uric acid appeared with the peak potential of 0. 980V and 0. 600V respectively at the modified electrode in pH 3. 0 phosphate buffer solution. The oxidation peaks of xanthine and uric acid were separated at 380 mV. Under the optimum conditions, the linear ranges for the determination of xanthine and uric acid were 1 . 00 × 10-6-2 . 50 × 10-4 mol/L respectively by differential pulse voltammetry. The detection limits were 5. 0×10-7mol/L. The method has been applied to the simultaneous detection of xanthine and uric acid in healthy human urine with satisfactory results.
ABSTRACT
The silver doped poly(L-aspartic acid) modified electrode was prepared by cyclic voltammetric method. The voltammetric behavior of dopamine and cyclic voltammetric method for the determination of dopamine were studied on the silver doped poly(L-aspartic acid) modified electrode. In pH 7.0 phosphate buffer solution, the peak potential was 0.191 V of Epa and 0.161 V of Epc(vs.Ag/AgCl) at the scan rate of 50 mV/s. The linear ranges for the determination of dopamine were 3.0×10-7-1.0×10-5 mol/L and 1.0×10-5-5.0×10-4 mol/L. The detection limit was 5.0×10-8 mol/L. The method was applied to the determination of dopamine in drug and urine with satisfactory results.