Differential Pulse Voltammetric Determination of Dopamine with Poly-p-Aminobenzene Sulfonic Acid Modified Electrode

Poly-p-Aminobenzene sulfonic acid modified electrode was prepared by electrochemical polymerization of p-aminobenzene salfonic acid on the surface of glassy carbon electrode,and electrochemical behavior of this modified electrode were studied by cyclic voltammetry and differential pulse voltammetry. It was found that in PBS of pH 7.0,a sensitive oxidation peak of dopamine was observed at 0.148 V. Linear relationship between values of peak current and concentration of dopamine was kept in the range of 4.0×10-7-1.0×10-5mol·L-1,with detection limit (3S/N) of 1.0×10-7mol·L-1. The proposed method has been used in differential pulse voltammetric determination of dopamine in its injections,giving values of recovery and RSD′s (n=5) in the ranges of 91.0%-112.0% and 2.4%-3.2%,respectively.