基于纳米氧化铈-石墨烯修饰电极对环境水体中Pb(Ⅱ)的测定

Determination of Pb(Ⅱ) in environmental water by nano-ceria-graphene modified electrode

以Nafion溶液为粘合剂,基于石墨烯(Gr)-纳米CeO2复合材料制备了Gr/CeO2/Nafion/GCE修饰电极,通过差分脉冲阳极溶出伏安法(DPASV)研究了Pb(Ⅱ)在该修饰电极上的电化学行为,建立了一种测定Pb(Ⅱ)的电化学方法。优化了复合材料浓度及其比例、缓冲溶液pH、修饰量、富集电位和时间。在最优条件下,Gr/CeO2/Nafion/GCE峰电流对Pb(Ⅱ)在0.24~48.31μmol/L范围内具有良好的线性及重复性,检出限为4.3 nmol/L。干扰实验结果表明,除Cu(Ⅱ)外,水中常见阴阳离子对Pb(Ⅱ)检测干扰小,Cu(Ⅱ)浓度在10倍以内干扰也可接受。将该修饰电极用于4种复杂水样中Pb(Ⅱ)的检测,加标回收率为89.5%~107.7%。

Nafion solution as a binder, the Gr/CeO2/Nafion/GCE modified electrode was prepared based on graphene(Gr)-nano cerium oxide(CeO2) composite materials. The electrochemical behavior of Pb(Ⅱ) on the modified electrode was investigated using differential pulse anodic stripping voltammetry(DPASV).Subsequently, a determination method for Pb(Ⅱ) was established. The concentrations and ratio of composite materials, buffer solution pH, modification amount, enrichment potential and time were optimized. Under the optimal conditions, the peak current of Gr/CeO2/Nafion/GCE showed good linearity in the range of 0.24-48.31 μmol/L of Pb(Ⅱ), and the detection limit was 4.3 nmol/L. Interference experiments showed that the other common anions and cations in water samples caused little interference to Pb(Ⅱ) detection. Furthermore, the interference of Cu(Ⅱ) within 10 times is acceptable. The modified electrode was used to the detection of Pb(Ⅱ) in four complex water samples, and the recovery rates of the spiked assays were from 89.5% to 107.7%.