聚茜素红膜修饰电极控制电位扫描法分别测定多巴胺和抗坏血酸

研究了聚茜素红膜修饰电极(PARE)的制备及其对多巴胺(DA)和抗坏血酸(AA)的电催化性能,结果表明,在PARE上DA和AA具有不同的循环伏安行为,前者表现为一个准可逆过程,后者则为不可逆过程,并且二者的氧化峰电位分开近200mV.因此可通过控制不同的电位范围进行分步扫描,实现了对同一体系中DA和AA的分别测定,DA的还原峰电流和AA的氧化峰电流分别在8.0×10^-6～4.0×10^-3mol/L和4.0×10^-5～2.0×10^-2mol/L范围内与各自的浓度呈线性关系;检测限分别为8.0×10^-7mol/L和1.0×10^-5mol/L.同时与导数伏安法一步测定进行比较,结果令人满意.

Respective Determination of Ascorbic Acid and Dopamine by Controlling Potential Sweeping on the Polyalizarin Red Film Modified Electrode

The preparation of polyalizarin red film modified electrode(PARE) and its electrocatalytic properties to dopamine(DA) and ascorbic acid(AA) were investigated. DA and AA have different voltammetric behaviour on PARE. The electrode reaction of DA on PARE is a quasi reversible process, but the oxidation of AA on PARE is a completely irreversible reaction. The oxidation peak of DA can be separated from that of AA about 200 mV on PARE. Passing through sweep for two times in different potential ranges, DA and AA can be detected in the same system respectively. The reduction peak current of DA is proportional to its concentration in the range of 8×10^-6 -4×10^-3 mol/L and the detect limit can reach 8×10^-7 mol/L. The oxidation peak current of AA is linear with its concentration from 4.0×10^-5 mol/L to 2.0×10^-2 mol/L. Detect limit of it reaches 1.0×10^-5 mol/L. Compared to the direct derivative voltammetry, the analysis results are very satisfactory.