对硫磷在纳米氧化铝薄膜修饰电极上的电化学行为及其测定

摘要

The electrochemical behaviors of parathion(PT) on nano-Al2O3 film modified electrode(nano-Al2O3/GCE/CME) were investigated. It was found that the redox peak currents of PT remarkably increased and the oxidation peak potential negatively shifted at the nano-Al2O3/GCE/CME. All the experimental parameters were optimized and a simple and sensitive electroanalytical method was developed for the determination of PT. The oxidation peak current was linear with the concentration of PT over the range from 2.5×10-9 to 1.0×10-7 mol/L and 1.0×10-7 to 1.0×10-5 mol/L. A low detection limit of 1.0×10-9 mol/L was obtained for 30 s accumulation at open circuit(S/N=3). The relative standard deviation(n=10) was 3.8% for 1×10-5 mol/L PT. The proposed method was used for the quantitative analysis of PT in some vegetables and the results were satisfactory.%制备了纳米氧化铝修饰玻碳电极(nano-Al2O3/GCE/CME),用循环伏安法(CV)、线性扫描伏安法(LSV)研究了对硫磷(TP)在nano-Al2O3/GCE/CME上的电化学行为.实验表明,该修饰电极与裸电极相比能显著提高TP的氧化还原峰电流并降低其氧化峰电位.在0.1 mol/L HAc-NaAc缓冲溶液(pH =5)中,TP在该修饰电极上产生1个不可逆的还原峰( Epc1=-0.567 V)和1对可逆氧化还原峰( Epa2=0.018 V和Epc2=-0.008 V) ,氧化峰电流与TP的浓度在2.5×10-9～1.0×10-7 mol/L和1.0×10-7～1.0×10-5 mol/L范围内具有良好的线性关系,回归方程分别为: ip(μA)=0.2529+4.201C(μmol/L), r=0.9984和ip(μA)=0.6752+0.3181C(μmol/L), r=0.9946.开路富集30 s后,检出限为1.0 ×10-9 mol/L(S/N=3).在1.0×10-5 mol/L TP试液中连续测定10次,其RSD为3.8%.用此方法测定了蔬菜中TP的含量,回收率为95. 6%～100.5% ,结果满意.