Study on the electrochemical behavior of dopamine with poly(sulfosalicylic acid) modified glassy carbon electrode

A glassy carbon electrode was modified with electropolymerized films of sulfosalicylic acid in pH 5.5 phosphate buffer solution (PBS) by cyclic voltammetry. The modified electrode showed an excellent electrocatalytical effect on the oxidation of dopamine (DA). In PBS of pH 7.4, the oxidation current increased linearly with two concentration intervals of dopamine, one is 5.5×10-7 to 2.2×10-5 M, the other is 2.2×10-5 to 1.1×10-4 M, with correlation coefficients of 0.9985 and 0.9996, respectively. The detection limit obtained by differential pulse voltammetry (DPV) was 5.0×10-9 M. The proposed method showed good sensitivity, reproducibility, stability and recovery for the determination of DA. The interference of ascorbic acid (AA) with the determination of DA could be efficiently eliminated.