稀土杂多酸盐修饰电极的制备及其对多巴胺在抗坏血酸共存下的选择性测定

目的: 制备稀土杂多酸盐修饰电极,研究多巴胺(DA)在修饰电极上的电化学行为,并在大量抗坏血酸(AA)共存时对DA的含量进行测定。方法: 电化学阻抗法(EIS)、循环伏安法(CV)、差分脉冲伏安法(DPV)。结果: 制备的修饰电极在硫酸溶液中呈现两对准可逆的氧化还原峰,电子转移数分别为2和4,修饰电极对DA有明显的电催化作用。采用CV法和DPV法都能将DA和AA的氧化峰分开。用两种方法测定DA含量,当DA浓度在1×10^-7~5×10^-4mol·L^-1(CV法)、5×10^-7~1.2×10^-5 mol·L^-1(DPV法)范围内,氧化峰电流与DA浓度呈现良好的线性关系。结论: 建立了一种在大量AA共存下测定DA的电化学方法,可用于样品中DA的测定。

Objective: The electrode modified with rare earth heteropoly acid salt was prepared. Electrochemical behaviors of dopamine (DA) in the modified electrode and selective determination of DA in the presence of large amount of ascorbic acid(AA) with the modified electrode were studied. Methods: Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry(CV) and differential impulsive voltammetry(DPV) were used. Results: The modified electrode in sulphuric acid solution presented two quasi-reversible redox peaks and the electron transfer number was 2 and 4, respectively. The modified electrode had obvious catalytic effects on DA. The oxidation peaks of DA and AA could be distinguished by using CV and DPV methods. There were a good linear relationships between the oxidation peak currents of DA and the DA concentration within the concentration scope of 1×10^-7–5×10^-4 mol·L^-1 (CV), 5×10^-7–1.2×10^-5 mol·L^-1 (DPV). Conclusion: The method of electrochemical determination of DA in the presence of large amount of AA is established, which can be used for the determination of DA in samples.