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

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

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Pb^(2+)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0.992 2;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 Pb^(2+)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。

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 4 h and 120 s,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 0.992 2.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）.