石墨烯钴膜修饰电极电化学法测定水体中的Hg(Ⅱ)

Electrochemical detection of Hg(Ⅱ)in water by graphene cobalt film-modified electrodes

通过电化学沉积法制备了以石墨烯为基体负载钴粒子的复合物膜修饰电极,实现了对水环境中Hg(Ⅱ)的快速、准确检测。采用电化学阻抗谱(EIS)对修饰电极进行表征,采用循环伏安法(CV)研究了Hg(Ⅱ)在该修饰电极上的电化学行为。优化了石墨烯浓度及其修饰量、CoCl_(2)浓度、缓冲液类型、沉积时间和沉积电位。在优化条件下,Hg(Ⅱ)在石墨烯钴膜修饰电极上具有很好的电流响应,与Hg(Ⅱ)浓度在4.99~498.53μmol/L范围内具有良好的线性关系,检出限为4.12μmol/L。抗干扰实验结果表明,该修饰电极对Hg(Ⅱ)的选择性较好。将该修饰电极用于自来水中Hg(Ⅱ)的检测,加标回收率为90.3%~102.6%,表明该修饰电极具有监测Hg(Ⅱ)的应用潜力。

The composite film-modified electrode based on graphene and loaded with cobalt particles was constructed by the electrochemical deposition method,which can realize rapid and accurate detection of Hg(Ⅱ)in water.The fabricated electrode was characterized by electrochemical impedance spectroscopy(EIS),and the electrochemical behavior of Hg(Ⅱ)on the modified electrode was studied by cyclic voltammetry(CV).Parameters including the graphene concentration,the modification amount,CoCl_(2)concentration,buffer type,deposition time,and deposition potential were optimized.Under the optimal conditions,Hg(Ⅱ)exhibited a good current response on the graphene cobalt film-modified electrode,and there was a linear relationship between the current and Hg(Ⅱ)concentration in the range of 4.99-498.53μmol/L,with a limit of detection of 4.12μmol/L.The graphene cobalt film-modified electrode had good anti-interference and selectivity for Hg(I1).The modified electrode was used for the detection of Hg(Ⅱ)in tap water,and the recoveries were 90.3%-102.6%,indicating the potential applications of the modified electrode in monitoring Hg(Ⅱ).