乙炔黑修饰电极上吡虫啉的电化学行为及测定

Electrochemical behavior and determination of imidacloprid on a acetylene black modified electrode

制备了乙炔黑修饰电极(AB/GCE),并用循环伏安法(CV)研究了吡虫啉(IDP)在该修饰电极上的循环伏安行为。在pH 9.0的NH3.H2O-NH4Cl缓冲液中,IDP在该电极上出现一不可逆的还原峰。在20～240mV/s扫速范围内,其还原峰电流(Ipc)与扫速平方根(v1/2)呈线性关系,表明该电极过程受扩散控制。计算了电极过程的部分动力学参数:电极有效面积为0.0635cm2,转移电子数为2,扩散系数为3.793×10-3cm2/s。运用方波伏安法测定不同浓度IDP的方波伏安曲线,还原峰电流Ipc与IDP浓度在7.0×10-7～8.0×10-5mol/L范围内呈良好线性关系(r=0.9975),检出限为2.29×10-7mol/L,加标回收率为93.5%～105.3%。

A novel acetylene black glassy carbon electrode（AB/GCE） was prepared and used to determine imidacloprid（IDP） by cyclic voltammetry（CV）.The results indicated that in pH 9.0 NH3 · H2O-NH4Cl buffer solution,an obvious reduction peak of imidacloprid appeared on the modified electrode.The reduction peak current was linear to v1/2in the range of 20-240 mV/s,indicating that the electrode process was controlled by diffusion.Some important kinetic parameters of the electrochemical process were determined：the effective area of AB/GCE was calculated to be 0.0635cm2,the electron transfer number（n） was 2;the diffusion coefficient（D） was 3.793×10-3 cm2/s.The peak current was linear over imidacloprid concentration in the range of 7.0×10-7-8×10-5 mol/ L.with a correlation coefficient of 0.9975and the detection limit was 2.29× 10-7mol/L.The re-coveries were in the range of 93.5%-105.3%.