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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 prepared by drop-coating method using the structural characteristics of nano-TiO2. The differential pulse stripping voltammetry was used to detect trace amounts of copper in water samples. The electrochemical behavior of Cu2 + on the nano-TiO2 / Nafion modified gold electrode was studied in detail. The effects of the thickness of nano-TiO2 / Nafion membrane, the solution pH, the enrichment potential and the enrichment time on the electrochemical properties of Cu2 + influences. The experimental results show that in pH = 2.0 nitric acid solution, potentiostatic stirring at -0.5 V for 240 s, standing for 10 s after anodic scanning, Cu2 + at about 0.25 V anode dissolution peak. Compared with the bare gold electrode, the peak current is greatly increased, indicating nano-TiO2 has a certain sensitivity to the dissolution of Cu2 +. Under the optimized experimental conditions, the peak current of Cu2 + showed a good linear relationship with the concentration of 10 ~ 900 nmol / L with the detection limit of 3.2 nmol / L. The modified electrode has a certain anti-interference ability, it is applied to the national standard samples and tap water samples Cu2 + detection, the results are satisfactory.