石墨烯修饰电极差分脉冲伏安法测定微量Cu^(2+)

Determination of trace Cu^(2+) by differential pulse voltammetry with graphene modified electrode

采用改进的Hummer方法合成氧化石墨烯,以石墨烯修饰玻碳电极(GCE)为工作电极,于-0.5 V吸附富集后差分脉冲伏安法测定微量Cu^(2+)。对石墨烯修饰电极进行了电化学表征,优化了石墨烯还原电位、还原时间、支持电解质、pH值、Cu^(2+)富集时间。实验结果表明,石墨烯修饰电极明显增强了铜溶出信号,溶出峰电流与Cu^(2+)的浓度在0.0005~1μg/mL范围内呈现良好的线性关系,线性方程为y=25.9208x-0.0255(r=0.9994),检测下限为0.0005μg/m L,所制备的修饰电极重现性和重复性较好,6次测定的相对标准偏差(RSD)分别为3.98%和3.51%,所提出的检测方法简单、灵敏、快速,无需复杂的样品前处理,修饰电极可反复使用,能应用于实际水样中铜离子的快速测定。

The graphene oxide was synthesized by the improved Hummer method. The graphene modified glassy carbon electrode（GCE） was used as work electrode to determine trace Cu2＋ by differential pulse voltammetry after the Cu2＋ ion was deposited at-0.5 V. The graphene modified GCE was characterized by electrochemical method. The reduction potential and time for graphene oxide, the supporting electrolyte, p H and deposition time were optimized.In comparison with the bare GCE, the response signal of the graphene modified GCE was obviously increased. Under the optimal conditions, the linear calibration curve ranged from 0.0005 to 1 μg/m L was obtained. The linear equation was y = 25.9208x-0.0255（r =0.9994）. The determination limit was 0.0005 μg/m L. The reproducibility and repeatability were also investigated with RSD of 3.98%（n=6） and 3.51%（n=6）, respectively. Owing to its simple fabrication, high sensitivity, fast response, good stability and repeatability, the developed sensor is promising for detecting Cu2＋ in real samples.