多巴胺在dsDNA/Ni2+/聚邻氨基酚修饰碳糊电极上的伏安行为

通过电化学聚合法在碳糊电极上共聚制备了聚邻氨基酚/Ni2+膜(Ni2+/P-OAP/CPE), 研究了膜的伏安特性, 并制成dsDNA修饰电极, 通过电化学和紫外光谱法进行表征. 将dsDNA/Ni2+/P-OAP/CPE电极应用于多巴胺的电催化氧化, 同时将该方法用于盐酸多巴胺针剂的测定, 亦获得了满意的结果.

Voltammetric Behavior of Dopamine at dsDNA-modified Ni2+/poly(o-aminophenol) Carbon Paste Electrode

The Ni2+/poly(o-aminophenol) electropolymerization was carried out by a continuous cyclic voltammetric scanning at a carbon paste electrode in a mixture of 0.02 mol/L o-aminophenol, 0.3 mol/L NiSO4 and 0.6 mol/L HClO4. dsDNA was linked to the conducting polymer via three-dimensional structure of polymer film and electrostatic attraction between the negatively charged phosphate backbone of DNA and Ni2+ ion. The results were testified by the electrochemical methods by using Co(phen)2+3 as an electrochemical indicator. The currents of redox peaks of Co(phen)2+3 increased after immobilizing dsDNA. The conditions for the preparation of Ni2+/P-OAP/CPE and DNA immobilization were optimized. The voltammetric behavior of dopamine was investigated at the modified electrode. It was found that the modified electrode exhibited a highly electrocatalytic activity toward dopamine oxidation. Differential pulse voltammetry was used for determination of dopamine in pH 5.1 phosphate buffer solution. A linear response of the peak current versus the concentration was found in the range from 5.0×10-6 to 2.0×10-4 mol/L with 1.0×10-2 mol/L AA(ascorbic acid) coexisting. The presence of a high concentration of AA did not interfere with the determination. The proposed method exhibits a good recovery and reproducibility.