半胱氨酸修饰的掺硼金刚石电极用于尿酸的测定

Electroanalysis of uric acid at a boron-doped diamond electrode modified with cysteine

在掺硼金刚石电极表面修饰聚半胱氨酸的电极测定尿酸时抗坏血酸和多巴胺的干扰较低。在方波伏安信号中抗坏血酸或多巴胺与尿酸共存检测时尿酸的特征峰电位变化较小(不超过15mV),峰电流变化只有几微安培。利用循环伏安法、方波伏安法对比了修饰电极与没有经过修饰的电极对尿酸的响应,试验了扫描速度、方波振幅、pH值等对修饰电极性能的影响。在最优条件下,得到测定尿酸的线性范围为1.45×10-9～1.16×10-6mol/L。在上述定性定量分析的基础上对未经预处理的儿童肾病病人尿样进行了检测,得到了令人满意的结果。

A boron -doped diamond electrode （BDDE） electrochemically modified with cysteine was used for monitoring uric acid （UA） by cyclic voltammetry （CV） and square wave voltammetry （SWV）. Owing to the distinct ability of the modified boron - doped diamond electrode to yield its best performance, the major obstacle in monitoring UA was overcome from the interference from ascorbic acid （AA） and dopamine coexisting with each other owing to the welldefined performance.of,BDDE. There are different peak potentials between UA and AA or dopamine at the modified boron - doped electrode, moreover, the modified BDDE exhibited superior electrochemical properties that the peak current of UA was in direct proportion to scan rate, indicative of a surface confined reduction process and that obtain a sensitive amperometric response for UA which covered linearly from 1.45 × 10^ - 9 mol / L to 1.16 × 10 ^- 6 mol / L under the optimum conditions with good stability and satisfactory detecting results.