MgAl水滑石和纳米Fe_2O_3复合膜修饰玻碳电极检测Cd^(2+)

The glassy carbon electrode modified with MgAl hydrotalcite and nano-Fe_2O_3 composite film used for determination of Cd^(2+)

采用沉淀法合成了镁铝水滑石和纳米Fe_2O_3,进行了XRD和IR表征.将两者按一定比例混合,制备成修饰的玻碳电极.采用示差脉冲伏安法详细研究了Cd^(2+)在修饰玻碳电极上的电化学响应行为,并对各种实验影响因素进行了优化.结果表明,在0.2 mol/L且pH=6.0的磷酸盐缓冲溶液中,当MgAl-HT与Fe_2O_3质量比为2∶1,制膜的滴涂量为9μL时,1×10^(-6)mol/L的Cd^(2+)在-1.0 V富集1.5 min后,进行电化学扫描,Cd^(2+)在-0.82 V附近出现一灵敏尖锐的溶出峰,溶出峰电流与其浓度在2×10^(-10)~2×10^(-8)mol/L范围内呈良好线性关系,检出限为1.0×10^(-10)mol/L,表明复合膜修饰玻碳电极检测镉离子效果很好.

Mg Al hydrotalcite and nano Fe2O3 were prepared by a precipitation method. The prepared samples were characterized by XRD and IR. The modified glassy carbon electrode was prepared by using both of them. The electrochemical behavior of Cd^2＋on the modified glassy carbon electrode was studied by stripping voltammetry in details. The results indicated that the optimum condition was as follows： 0.2 mo L/L Na H2PO4-Na2HPO4 buffer solution with pH = 6.0,with the mass ratio of MgAl-HT ∶Fe2O3= 2 ∶ 1 and 9 μL the amounts of composite films,after 1.5 min enrichment at-1.0 V,a sensitive stripping peak appeared at-0. 82 V at the chemical curve of 1 × 10^-6mol/L Cd^2＋solution. The stripping peak current was linear with concentration of Cd^2＋in the range of 2 × 10^-10-2 × 10^-8 mol/L,and the detection limit was 1×10^-10 mol/L.