石墨烯-离子液体修饰玻碳电极同时测定矿石中铅和镉

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

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。

The graphene（GR）dispersion was coated onto glass carbon electrode（GCE）to prepare GR/GCE electrode.The ionic liquid（1-octyl-3-methylimidazolium hexafluorophosphate,OMIMPF_6）was polymerized on the surface of GR/GCE electrode by cyclic voltammetry to prepare the novel OMIMPF_6/GR/GCE modified electrode.The electrochemical behaviors of Pb（2＋）and Cd（2＋）on OMIMPF_6/GR/GCE electrode were studied by differential pulse voltammetry using 0.1mol/L HAc-NaAc buffer solution（pH 4.5）as supporting electrolyte.The results showed that Pb（2＋）and Cd（2＋）had good electrochemical behaviors on the modified electrode.The concentration of Pb（2＋）and Cd（2＋）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）.