超声辅助萃取-直接测汞法测定海产品中的甲基汞

目的建立超声辅助溶剂萃取——直接测汞法测定海产品中甲基汞的检测方法,应用此方法检测黄鱼、鳕鱼、金枪鱼、扇贝、杂色蛤等海产品中甲基汞的含量。方法选择盐酸为萃取溶剂,通过优化萃取溶剂的浓度和提取条件,选择5 mol/L盐酸作为溶剂,超声1 h,以二氯甲烷分两次萃取,再以水反萃取,应用测汞仪直接测定水相中甲基汞的含量。结果甲基汞标准曲线的线性相关系数大于0.997,检出限为0.75 ng/g。不同类型生物标准参考物质实际测定值与标准参考值相符,测定值的相对标准偏差小于4%。结论该方法操作简便、快速、准确,适用于鱼、贝类海产品中甲基汞的快速萃取分离和测定。不同种类样品中甲基汞污染程度不同,实验选取的样品中甲基汞的含量均未超过卫生限量,鳕鱼、金枪鱼中甲基汞含量较高。

Determination of methylmercury in seafood by ultrasonic-assisted extraction coupled with direct mercury analyzer

Objective To establish a method for determination of methylmercury (MeHg) in seafood using a direct Hg analyzer (DMA-80), and apply this method to detect the content of MeHg in Yellow croaker, cod, tuna, scallops, and clams. Methods MeHg was separated from bio sample matrix with 5 mol/L hydrochloric acid by ultrasound assisted for 1 h. The extraction conditions were optimized. After back-extraction of MeHg from organic methylene chloride solvent to aqueous solution, MeHg was determined by the mercury analyzer. Results The standard curve of linear correlation coefficient was greater than 0.997, and the detection limit of MeHg was 0.75 ng/g. The experimental results of standard reference materials were in a good agreement with the certified values, and the relative standard deviation of the determined values were less than 4%. Conclusion The method takes the advantage of simplicity and accuracy, and can be applied for the analysis of MeHg in different seafoods. There is obvious difference of MeHg content levels in seafood samples. The MeHg content in experimental samples do not exceed the health limits, and MeHg content is higher in cod and tuna.