基于两电极体系检测水中微量汞

针对水体中常见重金属汞的检测问题,提出基于两电极体系的检测新方法.设计以金电极为工作电极、不锈钢为辅助电极的集成电极,用该电极对汞进行溶出伏安法测定.讨论活化电极、支持电解质、富集电压和富集时间对汞离子测定的影响.在优化的实验条件下,分别对1~10 μg/L和10~90 μg/L 2个不同浓度范围的Hg2+进行测定,溶出峰电流与Hg2+浓度呈良好的线性关系,相关系数分别为0.994 1和0.999 2；当富集时间为600 s时,Hg2+的检出限可以达到0.5 μg/L.利用该方法测定自来水中汞的含量,检测结果与原子吸收法一致,平均回收率为98%.结果表明,基于两电极体系,可以可靠、准确检测出水中汞,且电极灵敏度高、价格低廉,具有推广应用前景.

Determination of trace mercury in water based on two-electrode system

Aiming at the common detection problems of mercury in water, a new detection method was proposed. With gold electrode as working electrode and stainless steel as counter electrode, an integrated electrode was designed and used for mercury determination by stripping voltammetry. Electrode activation, chemical and instrumental variables such as supporting electrolyte, deposition potential and deposition time were optimized. In the optimized experimental conditions, two series of mercury solution with different concentrations were detected. The stripping current was linearly related to the concentration of mercury (Ⅱ) in the range of 1~10μg/L (R2=0.994 1) and 10~90 μg/L (R2=0.999 2), with a detection limitof 0.5μg/L under 600 s accumulation.The integrated electrode was further used to detectmercury in tap water, and the obtained results revealed a good agreement with atomicabsorption spectroscopy (AAS).The new method based on two-electrode system can reliably and accurately detect mercury in water. The integrated electrode is highly sensitive, environmental friendlyand cheap, suitable for promotion and application.