石墨烯修饰玻碳电极应用于甲基对硫磷的快速测定

摘要

为了研究有机磷农药-甲基对硫磷(MP)的快速检测方法,用石墨烯(GR)-壳聚糖(CS)复合物修饰玻碳电极(GCE),用循环伏安法(CV)和差分脉冲伏安法(DPV)研究了MP的电化学行为,与GCE电极相比,发现其氧化还原电流信号明显增强,表明修饰电极对MP具有较强的吸附作用,并能够加速电子传递.对缓冲溶液的pH、富集时间及纳米粒子的负载量等实验条件进行了优化,在最佳条件下,发现氧化峰电流与MP浓度在0.01 ～4.μg/mL范围内呈现良好的线性关系,线性方程为I(μA)=-1.1467-3.5646C(μg/mL)(R2 =0.996 3),检测下限为2.7ng/mL (S/N =3),该修饰电极具有良好的重现性和稳定性.将该修饰电极应用于实际样品分析,加标回收率为95.1％～102.5％.%To study the rapid detection method of organophosphorus pestic1de-memyl paratmon (MP),An electrochemical sensor for the detection of MP was developed based on graphene (GS)and chitosan (CS) composites modified glassy carbon electrode (GS-CS/GCE).Electrochemical behavior of MP on the modified electrode was investigated thoroughly using cyclic voltammetry (CV) and differential pulse voltammetry (DPV).It found that the Redox current at GR-CS /GCE electrode was obviously larger than that at GCE electrode,indicating that the GR-CS/GCE electrodes has strong adsorption to MP,and can accelerate the electron transfer.Experimental parameters,including pH of buffer solution,the amount of nanoparticles and accumulation time were optimized.Under the optimal conditions,the oxidation peak current was proportional to methyl parathion concentration in the range between 0.01 and 4 μg/mL,the linear equation was I (μA) =-1.146 7-3.564 6C (μg/mL) (R2 =0.996 3) and a detection limit was 2.7 ng/mL (S/N =3) and modified electrode has a good repeatability and stability.Finally,the modified electrode was successfully employed to determine the methyl parathion in real samples and the recoveries were between 95.1％ and 102.5％.