Voltammetric Behavior of Dopamine at ct-DNA Modified Carbon Fiber Microelectrode.

A sub-micrometer thin-layer DNA modified carbon fiber microcylinder electrode was prepared by electrodeposition of ct-DNA at 1.5 V (vs. Ag/AgCl). The voltammetric behavior of dopamine (3-hydroxytyramine) was investigated at the modified electrode. It was found that the modified electrode exhibits a highly electrocatalytic activity toward dopamine oxidation. Differential pulse voltammetry was used for determination of dopamine in pH 7.4 phosphate buffer solution. A linear response of the peak current versus the concentration was found in the range of 4 × 10^-6 to 10^-4 mol L^-1 at 10^-4 mol L^-1 AA (ascorbic acid) coexistence (R = 0.9959) and the range of 6 × 10^-5 to 10^-3 mol L^-1 at 10^-3 mol L^-1 AA (R = 0.9960). The presence of a high concentration of ascorbic acid did not interfere with the determination. The proposed method exhibited good recovery and reproducibility. This method can be applied to the detection of DA in real samples. [ABSTRACT FROM AUTHOR]