碲化镉/石墨烯修饰玻碳电极差分脉冲伏安法测定矿石中痕量铅

准确测定痕量铅,对保护人类健康具有重要意义。采用CdTe量子点和石墨烯制备了CdTe/石墨烯/玻碳(CdTe/GR/GCE)修饰电极,并通过差分脉冲伏安法测定矿石中痕量铅含量。通过循环伏安曲线考察了修饰电极在CdTe溶液中的自组装时间,浸泡时间和富集时间分别为4h、120s;测定时HAc-NaAc缓冲溶液的pH值为5.0;最佳条件下Pb²⁺浓度在1.0×10^-8~1.0×10^-4 mol/L范围内与其峰电流呈良好的线性关系,相关系数为0.9922;检出限为4.0×10^-9 mol/L。利用5个修饰电极按照实验方法对1.0×10^-6 mol/L Pb²⁺溶液检测,结果的相对标准偏差(RSD,n=6)为4.3%和5.5%(3d后);采用实验方法测定矿石中铅,结果的相对标准偏差(RSD,n=10)为2.9%~4.0%,与原子吸收光谱法(AAS)测定结果相吻合。

Determination of trace lead in ore by differential pulse voltammetry using cadmium telluride/graphene modified glassy carbon electrode

The determination of trace lead is of great significance to the protection of human health. The cadmium telluride/graphene modified glassy carbon electrode (CdTe/GR/GCE) was prepared using CdTe quantum dot and GR. Then the content of trace lead in ore was determined by differential pulse voltammetry. The self-assembly time of modified electrode in CdTe solution was investigated by cyclic voltammetry curve. The optimum immersion time and enrichment time was 4h and 120s, respectively. The pH of HAc-NaAc buffer solution for determination was 5.0. Under the optimized conditions, the concentration of Pb²⁺ in range of 1.0×10^-8-1.0×10^-4 mol/L showed good linear relationship with its peak current. The correlation coefficient was 0.9922. The detection limit was 4.0×10^-9 mol/L. 1.0×10^-6 mol/L Pb²⁺ solution was determined according to the experimental method using five modified electrodes. The relative standard deviations (RSD, n=10) of determination results ranged from 2.9% to 4.0%. The found results were consistent with those obtained by atomic absorption spectrometry (AAS).