纳米氧化铁修饰玻碳电极检测痕量镉离子

制备了一种纳米氧化铁修饰玻碳电极,并研究了镉离子在该修饰电极上的溶出伏安行为。结果表明,纳米氧化铁颗粒能有效促进镉离子的溶出伏安响应。在pH 6.0的磷酸缓冲溶液中,镉离子能有效吸附在纳米氧化铁表面并在-1.0 V时被还原。被还原的镉在正向扫描过程中可以重新氧化,并在-0.85 V处出现一明显的溶出伏安氧化峰。该峰电流随镉离子浓度的增大而增大,可用于对镉离子的检测。在最佳检测条件(pH 6.0,富集时间350 s,富集电位-1.0 V)下,镉离子的响应电流与其浓度在6.0×10-10～1.0×10-8mol/L以及1.0×10-8～1.0×10-5 mol/L范围内呈良好线性,检出限(S/N=3)为1.0×10-10 mol/L。干扰实验结果表明,一些常见的阳离子以及阴离子对镉离子的检测无明显干扰。将该方法用于实际样品的检测,回收率良好。

Determination of Trace Cadmium Ion on a nano-Fe2O3 Modified Glassy Carbon Electrode

A nano-Fe2O3 modified glassy carbon electrode(Fe2O3/GCE) was fabricated and the stripping voltammetry behavior of cadmium ion on this modified electrode was studied.The results indicated that the presence of Fe2O3 nanoparticles can effectively enhance the stripping voltammetric response of cadmium ion.In pH 6.0 phosphate buffer solution,cadmium ion was adsorbed onto the surface of Fe2O3 nanoparticles effectively and then reduced at-1.0 V.During the positive potential sweep,the reduced cadmium was oxidized again and an obvious stripping oxidation peak was observed at about-0.85 V.The current of the stripping peak was increased with the increase of cadmium ion concentration.Based on this,a novel method for the determination of cadmium ion was developed based on nano-Fe2O3 modified electrode(Fe2O3/GCE).The experimental conditions were optimized.Under the optimum conditions(pH value:6.0,accumulation time:350 s,accumulation potential:-1.0 V),the current response of cadmium ion increased linearly with concentration of cadmium ion in the ranges of 6.0×10-10-1.0×10-8 mol/L and 1.0×10-8-1.0×10-5mol/L,with a detection limit of 1.0×10-10 mol/L at 3σ.Some common metal ions and cations had no obvious effects on the determination of cadmium ion.This method was used in the determination of cadmium ion in real water samples with satisfactory recovery.