石墨烯-离子液体修饰玻碳电极同时测定矿石中铅和镉

将石墨烯(GR)滴涂在玻碳电极(GCE)上制备GR/GCE电极,采用循环伏安法将离子液体(1-辛基-3-甲基咪唑六氟磷酸盐)聚合在GR/GCE电极表面,制得新型OMIMPF_6/GR/GCE修饰电极。以0.1mol/L HAc-NaAc缓冲溶液(pH 4.5)为支持电解液,利用差分脉冲法研究了Pb~(2+)和Cd~(2+)在OMIMPF_6/GR/GCE电极上的电化学行为。结果表明,Pb~(2+)和Cd~(2+)在修饰电极上有较好的电化学行为,Pb~(2+)和Cd~(2+)的浓度分别在1.0×10~(-8)~4.2×10~(-5)mol/L和1.0×10~(-8)~6.0×10~(-5)mol/L范围内与峰电流呈良好的线性关系;Pb~(2+)和Cd~(2+)的检出限分别为1.0×10~(-9) mol/L和5.0×10~(-8)mol/L。实验方法用于矿石中铅和镉的测定,结果的相对标准偏差(RSD,n=6)为2.9%~4.4%;并与原子吸收光谱法对比,测定结果基本一致。

Simultaneous determination of lead and cadmium in ores by graphene-ionic liquid modified glassy carbon electrode

The graphene (GR) dispersion was coated onto glass carbon electrode (GCE) to prepare GR/GCE electrode. The ionic liquid (1-octyl-3-methylimidazolium hexafluorophosphate, OMIMPF₆) was polymerized on the surface of GR/GCE electrode by cyclic voltammetry to prepare the novel OMIMPF₆/GR/GCE modified electrode. The electrochemical behaviors of Pb²⁺ and Cd²⁺ on OMIMPF₆/GR/GCE electrode were studied by differential pulse voltammetry using 0.1 mol/L HAc-NaAc buffer solution (pH 4.5) as supporting electrolyte. The results showed that Pb²⁺ and Cd²⁺ had good electrochemical behaviors on the modified electrode. The concentration of Pb²⁺ and Cd²⁺ in range of 1.0×10^-8-4.2×10^-5 mol/L and 1.0×10^-8-6.0×10^-5 mol/L showed good linear relationship to the peak currents. The detection limit was 1.0×10^-9 mol/L and 5.0×10^-8 mol/L, respectively. The proposed method was applied to the determination of cadmium and lead in ore samples. The relative standard deviation (RSD,n=6) of determination results were between 2.9% and 4.4%. The found results were consistent with those obtained by atomic absorption spectrometry (AAS).