甲氧苄啶的电化学氧化及伏安测定法___

目的：研究甲氧苄啶的电化学性质，初步探讨甲氧苄啶在电极上的响应机理，并用电化学方法对其进行检测。方法：在0.1 mol•L-1 KNO3底液中，用玻碳电极循环伏安法和示差脉冲扫描伏安法研究甲氧苄啶的电化学性质，并用示差脉冲扫描伏安法测定甲氧苄啶的含量。结果：甲氧苄啶的氧化峰电位是1.3 V，氧化峰电流与甲氧苄啶的浓度在2.0×10-5~4.2×10-3 mol•L-1范围内呈良好的线性关系。该测定方法的检出下限（3S/N）为4.0×10-6 mol•L-1。用标准加入法测定回收率范围在96.1%~101.6%，RSD为3.2%(n=5)。结论：甲氧苄啶在1.3 V处的氧化为4电子参加的受扩散控制的不可逆过程。甲氧苄啶的电化学测定方法能很好地用于实际样品的测定而且结果与2005年版中国药典方法一致。

Objective:It had been discussed that the electrochemistry characteristic and the reaction mechanism on a glassy carbon electrode of trimethoprim.The concentration of trimethoprim was determined by the method of electrochemistry.Methods:In the solution of 0.1 mol•L-1 KNO3,the electrochemistry properties of trimethoprim were researched with a glassy carbon electrode by the cyclic voltammetry and the differential pulse voltammetry and the concentration of trimethoprim was detected by the differential pulse voltammetry.Results:The potential of trimethoprim oxidation peak was 1.3 V and the peak currents were proportional to trimethoprim concentration in the range of 12.0×10-5-4.2×10-3 mol•L-1 with the detection limit of 4.0×10-6 mol•L-1.The range of recovery was 96.1%-101.6% by the standard addition,and RSD was 3.2%(n=5).Conclusions:The anodic oxide of trimethoprim at 1.3 V was irreversible diffusion-controlled and was characteristic of four electrons.This method was applied in detection the content of trimethoprim sample and the results obtained by this method were in conformity with the results found by pharmacopoeia method.

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