磁流体动力学用于镉的溶出伏安检测

Stripping Voltammetric Detection of Cadmium in Small Volume Samples Based on the Magnetohydrodynamics

提出了一种基于磁流体动力学效应用于小体积样品中镉的测定的溶出伏安方法。在金属的溶出伏安法测定中,磁场和高浓度的Fe3+的共同作用产生的磁流体动力学效应使得更多的金属离子沉积在电极表面,使金属的溶出峰电流明显提高,极大地提高了测量的灵敏度。在对2mL样品中的Cd测定,磁场强度0.6T,Fe3+浓度为0.12mol/L,富集电位-0.8V,富集时间60s,镉的检出限为3.1×10-9mol/L,线性范围为1×10-8～1×10-6mol/L。本方法灵敏度高、重现性好,可以有效的避免传统的溶出伏安法测定中,由搅拌所产生的较大的背景电流干扰,尤其适用于小体积样品中重金属离子的溶出伏安法分析。

A novel stripping vohammetric approach for the detection of cadmium based on magnetohydrody- namics was proposed. In the presence of magnetic field and Fe^3＋ with high concentrations, Magnetohydrody-namics effect was caused in the stripping voltemmetry. More metal ions were deposited on the electrode surface, and then the stripping peak current of metal and the sensitivity of the detection were obviously increased. In the determination of 2 mL cadmium samples, with the 0.6 T magnetic field strength, 0.12 mol/L Fe^3＋ concentrations, -0.8 V accumulation potential 60 s, accumulation time, the detect limit of 3.1×10^-9 mol/L was obtained, and the linear range was from 1×10^-8 mol/L to 1×10^-6 mol/L. The method possesses high sensitivity, good reproducibility, and could effectively avoid the large back current stemmed from the machine oscillation in the traditional stripping vohammetry. It was especially proper for the analysis of heavy metal ions in micro-samples.