替硝唑在碳糊电极上的电化学性质及电分析方法研究

Electrochemical behaviors of tinidazole at a carbon paste electrode and its electroanalytical application

运用循环伏安法（CV）、方波伏安法（SWV）研究替硝唑（TNZ）在碳糊电极（CPE）上的电化学行为、电化学动力学性质及可能的电极反应机理。TNZ在CPE上的伏安行为是一受扩散控制的不可逆电化学还原过程，还原峰电位（Epc）为-0．557V。用方波伏安法（SWV）测定TNZ线性范围为1．0×10^-5～1．0×10^-3mol／L。检出限3．3×10^-7 mol／L。RSD 1．3％-2．8％，加样回收率99．2％～100．6％。据此建立了TNZ含量的电化学测定方法。

Electrochemical behaviors of tinidazole （TNZ） and its electrochemical kinetic parameters at the carbon paste electrode （CPE） have been investigated by cyclic voltammetry（CV）, ehronoamperometry （CA） and ehronocoulometry （CC）. Electrochemical experimental results show that the electrochemical behavior of TNZ in 0.04 mol/L Britton-Robinson buffer （B-R） exhibits an irreversible electrochemical reduction process at the CPE, the reduction peak potential （ Epc ） is - 0. 557 V （ vs. SCE）. The plot of peak current versus the square root of the scan rate in the range of 10 - 800 mV/s show a straight line, as expected for a diffusion-limited electrochemical process. Electron transfer coefficient a, diffusion coefficient D and the reaction rate constant kf are 0.84, 1.12 × 10^-5 cm^2/s and 2.26 × 10^-3 s^-1, respectively. TNZ shows an irreversible reduction process with 4 electrons and 4 protons transferred at CPE. The peak current of TNZ versus its concentration have a good linear relationship in the concentration range of 1.0 × 10^-5 - 1.0 ^ 10^-3 mol/L with the correlation coefficient of 0.9991 and the detection limit of 3.3 × 10^-7 mol/L by SWV response. RSD is between 1.3% -2.8% and recoveries are in the range of 99.2% - 100.6%. The proposed method can be applied to TNZ determination with the satisfa results.