分散液液微萃取分光光度法测定食品中汞含量

Development of a dispersive liquid-liquid microextraction method for the spectrophotometric determination of mercury in food samples

建立了分散液液微萃取分光光度法测定食品中汞含量的方法。使用双硫腙、三氯甲烷、乙醇分别作为络合剂、萃取溶剂、分散溶剂,研究了萃取溶剂和分散溶剂体积、pH、络合剂浓度、萃取时间等影响因素。在最佳条件下,方法的线性范围为10~200ng·mL-1,相关系数（r）为0.9966,检出限为3ng·mL-1,对100ng·mL-1汞离子进行7次平行测定的相对标准偏差为4.3%。该方法可应用于鱼和茶叶中汞含量的测定。

Dispersive liquid-liquid microextraction （DLLME） technique combined with ultraviolet-visible spectrophotometry for the preconcentration and determination of mercury in food samples was developed. Dithizone,chloroform and ethanol were used as chelating agent,extraction solvent and disperser solvent, respectively. Some important DLLME parameters such as the volume of extraction and disperser solvent,pH, concentration of chelating agent and extraction time were investigated in detail. Under the optimized conditions,the calibration graph was linear from 10 to 200ng.mL-1 with a correlation coefficient of 0.9966. The limit of detection was 3ng. mL-1 and the relative standard deviation（n=7,for 100ng-mL-1 of mercury） was 4.3%. The method was successfully applied into the determination of trace amounts of mercury in fish and tea leaves.