离子交换伏安法测定人发中痕量镉的研究

Determination of Cd^(2+) in Human Hair by Ion exchange Voltammetry

报道了一种测定痕量镉的电化学分析方法。在 pH 4.0 0的磷酸盐缓冲溶液中 ,镉离子在钠型蒙脱石修饰玻碳电极上通过离子交换有十分灵敏的阳极溶出峰 ,且峰高与镉的含量相关。据此建立了测定痕量镉离子的方法 ,优化了各种试验条件 ,如支持电解质的选择、pH值的影响、修饰剂的用量、富集电位及时间、以及扫描速率。该方法测定镉时线性范围为 8×1 0 - 9～ 2× 1 0 - 6 mol/L ,检出限为 1× 1 0 - 9mol/L。方法简便、快速 ,灵敏度高。用此法测定了人发样品中的镉离子含量 ,结果令人满意。

A sodium montmorillonite modified glassy carbon electrode for the voltammetric determination of Cd 2+ was described. Cd 2+ were firstly preconcentrated on the surface of the sodium montmorillonite modified electrode via ion exhchange interaction, and then reduced. In the following step, reduced cadmium was stripped by applying voltammetric scanning. The experiment parameters, such as supporting electrolyte and pH values, amount of sodium montmorillonite, accumulation potential and time and scan rate, were optimized. It was found that the peak current was linear with the concentration in the range from 8×10 -9 mol/L to 2×10 -6 mol/L of Cd 2+ . The detection limit was 1×10 -9 mol/L for Cd 2+ . Using this modified electrode, trace levels of Cd 2+ in human’s hair samples were determined.