甲苯二次萃取-直接测汞法快速测定海产品中的甲基汞

DETERMINATION OF METHYL MERCURY IN SEA ORGANISMS BY TOLUENE EXTRACTION AND DIRECT MERCURY ANALYZER

建立了甲苯二次萃取-直接测汞的方法对生物样品中的甲基汞进行分析测定.样品经氢溴酸水解、甲苯萃取、L半-胱氨酸反萃取等前处理,应用DMA-80直接测汞仪测定.对甲基汞鱼肉标准物质(GBW 10029)和贻贝标准物质(SRM 2976)的实测结果显示,测定值与标准参考值的相对误差小于4%,测定值的相对标准偏差小于2%,甲基汞的检出限为0.64 n.gg-1,甲苯二次萃取的萃取率在95%—99%之间.该方法具有较高的准确度和精密度,适于鱼、贝等生物体中甲基汞的测定,并可将总汞和甲基汞的测定在一台仪器上完成.

A method for the determination of methylmercury（MeHg） in organism was developed using a direct Hg analyzer（DMA-80）.The analysis of MeHg in biota samples was performed by separating of MeHg from sample matrix with hydrobromic acid,extraction of MeHg with toluene and back-extraction of MeHg from organic solvent to cysteine aqueous solution.MeHg in cysteine aqueous solution was determined by the mercury analyzer.The relative error between the determined and the certified values of standard reference materials（GBW 10029,SRM 2976） was less than 4%,and the relative standard deviation of the determined values was less than 2%.The detection limit of MeHg was 0.64 ng·g-1.The total extraction efficiency was between 95% and 99%.This method can yield accurate and reliable result,and allows routine analysis of both total mercury and MeHg in organisms using the same instrument.