L-半胱氨酸修饰电极在高浓度抗坏血酸共存下测定多巴胺

目的为了研究多巴胺的测定,并有效排除抗坏血酸的干扰,制备了聚L-半胱氨酸修饰电极。方法通过电化学方法将L-半胱氨酸修饰到玻碳电极表面,采用线性扫描溶出伏安法对多巴胺进行定量分析。结果实验表明,该修饰电极对神经递质多巴胺的电化学氧化有显著的催化作用,峰电流明显增大,线性范围为2.0×10-7～1.0×10-4mol/L,检出限为2.0×10-8mol/L。结论该聚合物修饰电极具有良好的选择性,用于多巴胺的测定,能有效地排除抗坏血酸的干扰,结果令人满意。

Selective determination of dopamine in the presence of high concentration of ascorbic acid with L-cysteine modified glassy carbon electrodes

OBJECTIVE: To establish an assay system for determination of dopamine (DA) in the presence of ascorbic acid (AA) with L-cysteine modified glassy carbon electrode. METHODS: L-cysteine was modified onto glassy carbon electrode electrochemically, and with this modified electrode, dopamine was determined by linear sweep stripping voltammetry. RESULTS: L-cysteine polymer-modified electrode had strong catalytic effect towards the electrochemical oxidation of DA. The modified electrode showed good properties in determination of DA with coexisting AA. Under selected conditions, the linearity of DA was in the range of 2.0 x 10(-7) - 1.0 x 10(-4) mol/L with the detection limit of 2.0 x 10(-8) mol/L. The stability, reliability and recovery of this L-cysteine-modified electrode based on electrochemical method were also satisfactory. CONCLUSION: L-cysteine-modified electrode can avoid the interference by AA for determination of DA.