分散液液微萃取—分光光度法测定水中痕量汞

以四氯化碳为萃取剂,丙酮为分散剂,硫代米式酮(Thio-Michler’s ketone,TMK)为汞的螯合剂,建立了水中痕量汞分散液液微萃取—分光光度法测定的新方法.对分散液—液微萃取条件和分光光度法测定的最佳实验参数进行优化,包括溶液的pH值,萃取剂与分散剂的种类与用量,螯合剂硫代米式酮的用量,萃取时间等.在最佳实验条件下,汞的浓度在110～420 ng/mL范围内与吸光度呈良好线性关系,相关系数r=0.998 1,富集倍数为30,检出限为55 ng/mL,相对标准偏差(RSD)为4.2%(n=8),回收率为92%～108%.实验结果表明,该方法简便,快速,回收率高,成本低、富集效率高且对环境友好,适用于水中痕量金属汞的测定.

Determination of Trace Mercury in Waters by SpectrophotometryWith Dispersive Liquid-liquid Microextraction

A novel method for the determination of trace mercury in waters by dispersive liquid-liquid microextraction （DLLME） coupled with spectrophotometry has been devel- oped. The preposed method uses thio-Michler＇s ketone （TMK） as a chelating agent for mercury and carbon tetrachloride as an extraction solvent, acetone as a disperser. The pa- rameters for determination of mecury were optimized including the pH of solution, the che- lating agent for mecury, the types and dosages of extraction solvent, dispersant and the ex- traction time. Under the optimum conditions, the calibration curves were linear in the con- centration range 110 ~ 420 ng/mL for mecury with the correlation coefficient of 0. 9981. The detection limit was 55 ng/mL and the relative standard deviation （RSD） 8.3% （n = 8）. The method was used to determine trace mercury in water samples with the recoveries in the range of 92.0% ~ 108.0%. It exhibited a sensitive,rapid and easy-to-use methodfor the fast determination of trace mecury in water samples with high accuracy demonstra- ting its potential for practical application.