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山东师范大学化学化工与材料科学学院;中国科学院烟台海岸带研究所中国科学院山东省海岸带环境过程重点实验室;

利用纳米二氧化钛(nano-TiO2)的结构特性;采用滴涂法制备了一种nano-TiO2/Nafion修饰金电极;采用差分脉冲溶出伏安法实现了水样中痕量铜的检测。详细研究了Cu2+在nano-TiO2/Nafion修饰金电极上的电化学响应行为;并讨论了nano-TiO2/Nafion膜的厚度、溶液pH值、富集电位、富集时间等对Cu2+溶出峰电流的影响。实验结果表明:在pH=2.0硝酸溶液中;-0.5 V恒电位搅拌富集240 s;静置10 s后阳极化扫描;Cu2+在0.25 V左右出现阳极溶出峰。相比于裸金电极;该峰电流大大提高;表明nano-TiO2对Cu2+的溶出具有一定的增敏作用。在最优化实验条件下;10~900 nmol/L范围内;Cu2+的溶出峰电流与其浓度呈良好的线性关系;检出限可达3.2 nmol/L。该修饰电极具有一定的抗干扰能力;将其应用于国标样品和实际自来水样中Cu2+的检测;结果令人满意。

A nano-TiO2/Nafion modified gold electrode was developed to detect copper utilizing the properties of nano TiO2.Electrochemical behavior of Cu2＋ at nano-TiO2/Nafion modified gold electrode was studied by differential pulse stripping voltammetry.Experimental parameters such as amount of nano-TiO2/Nafion suspension,pH value of the supporting electrolyte,accumulation potential and accumulation time were optimized.Results indicated that a remarkable anodic peak appeared at 0.25 V when accumulating for 240 s at-0.5 V in HNO3（pH 2.0）solution with stirring.Compared to bare gold electrode,peak current enhanced greatly indicating the strong preconcentration of Cu2＋ at nano-TiO2/Nafion composite film.Under the optimized working conditions,the stripping peak currents were linear with concentrations of Cu2＋ over the range from 10 to 900 nmol/L.The detection limit was 3.2 nmol/L.The electrode with some anti-interference abilities for the determination of Cu2 ＋ can be used for the determination of Cu2 ＋ in national standard substance and tap water samples with satisfactory results.