吡虫啉在聚L-酪氨酸修饰电极上的电化学行为及其测定

Electrochemical Behavior and Determination of Imidacloprid with Polymeric L-Tyrosine Film Modified Electrode

采用循环伏安法研究了吡虫啉在制备的聚L-酪氨酸修饰电极上的电化学行为。结果表明,在pH 8.5的NH3.H2O-NH4C l缓冲溶液中,吡虫啉在聚L-酪氨酸修饰电极上的电化学行为是受扩散控制的不可逆电还原过程,转移电子数和质子数均为2,扩散系数D=5.15×10^-5cm^2.s^-1。吡虫啉的还原峰电流与其浓度在5.0×10^-7-8.0×10^-5mol.L^-1范围内呈良好的线性关系,线性方程为Ip（A）=2.435×10^-6＋0.809 5c（mol.L^-1）,r=0.998 6,检出限为2.36×10^-7mol.L^-1,样品测定回收率为94%-103%。

A poly（L-tyrosine） film modified electrode was fabricated,and electrochemical behavior of imidacloprid on the modified electrode was investigated.It was found that,in pH 8.5 NH3·H2O-NH4Cl buffer solution,the electrochemical reduction of imidacloprid on the modified electrode was irreversible,and was controlled by diffusion with a diffusion coefficient（D） of 5.15×10^-5 cm2·s^-1.The number of electron and proton transferred in the electrode reaction were 2.The relationship between peak current and the concentration of imidacloprid in the range of 5.0×10^-7-8.0×10^-5 mol·L^-1 met the linear equation：Ip（A） =2.435×10^-6＋0.809 5c（mol·L^-1） with a correlative coefficient（r） of 0.998 6.The detection limit was 2.36×10^-7 mol·L^-1.The recoveries of practical samples were between 94% and 103%.