甲氧苄啶在多壁碳纳米管-Nafion修饰电极上的电催化氧化及电分析方法

Electrocatalytic Oxidation of Trimethoprim at Multi-wall Carbon Nanotubes-Nafion Modified Glassy Carbon Electrode and Its Electrochemical Determination

用循环伏安法(CV),计时库仑法(CC),计时电流法(CA),线性扫描伏安法(LSV)及电流-时间曲线研究了甲氧苄啶(trimethoprim,TMP)在碳纳米管-Nafion修饰电极(MWCNTs-Nafion/GCE)上的电化学行为,电化学动力学性质以及电分析方法。结果表明,TMP在GCE上有一个极弱的氧化峰,而在MWCNTs-Nafion/GCE上出现一个敏锐的氧化峰,表明MWCNTs-Nafion/GCE对TMP电化学氧化具有良好的催化作用。在扫描速度为10～800mV/s时其氧化峰电流与扫描速度平方根(v1/2)呈良好线性关系,表明TMP在MWCNTs-Na-fion/GCE上的伏安行为是受扩散控制的电化学过程。TMP在MWCNTs-Nafion/GCE上氧化峰电流与浓度在5.0×10-6～1.0×10-3mol/L范围内呈良好线性关系;检出限为6.6×10-7mol/L;RSD在0.75%～1.69%之间;加标回收率在98.1%～101.1%之间。本方法简便快捷,测定结果令人满意,可用于TMP的电化学定量测定。

Electrochemical behaviors, electrochemical kinetics and electrochemical determination of trimethoprim （TMP） at muhi-wall carbon nanotubes-Nafion modified glassy carbon electrode （MWCNTs-Nafion/ GCE） were investigated by cyclic voltammetry （ CV ）, chronoeoulometry （ CC ）, chronoamperometry （ CA）, linear scan vohammetry（LSV） and amperometrie i-t curve. The experimental results showed that the direct electrochemical oxidation of TMP is sluggish on GCE, but the oxidation peak current of TMP increases significantly at MWCNTs-Nafion/GCE in comparison with that at bare GCE, which indicates that MWCNTs-Nafion/ GCE can catalyze the electrochemical oxidation of TMP very well. It has also been done that the research on the influence of the experimental conditions on TMP electrochemical behaviors. The results showed that the electrode reaction process is a diffusion-limited. At MWCNTs-Nafion/GCE, the oxidation peak current is proportional to the concentration of TMP over the range from 5.0 × 10^-6 to 1.0 × 10 ^-3 mol/L. The detection limit is 6.6 ×10^ -7 mol/L. The relative standard deviation is between 0.8% and 1.7% and the recovery is 98.1% - 101.1%. This MWCNTs-Nafion/GCE method has been applied in the determination of TMP in tablet samples with the satisfied results.