Xiong Chaomei, Hu Bin
Department of Chemistry, Wuhan University, Wuhan 430072, People's Republic of China.
J Agric Food Chem. 2007 Dec 12;55(25):10129-34. doi: 10.1021/jf071979b. Epub 2007 Nov 22.
A simple and effective method for the determination of trace amounts of methylmercury (MeHg(+)) and inorganic mercury (Hg(2+)) in seafood was developed by online microcolumn separation/preconcentration combined with inductively coupled plasma optical emission spectrometry (ICP-OES). It was found that Hg(2+) could be quantitatively adsorbed by YPA 4 resin from pH 7.0 to strong acidic medium (6 mol L(-1) HCl) and that MeHg(+) was retained by the YPA 4 microcolumn only at pH 1.0-7.0. Therefore, a strong acidic medium (about 5 mol L(-1) HCl), which could liberate mercury species from biological samples, was used to directly separate inorganic Hg(2+) from total Hg, and MeHg(+) in effluent was retained by YPA 4 column after the effluent was adjusted to pH 1.5. The effects of acidity, sample flow rate and volume, elution solution, and interfering ions on recovery of the two mercury species have been systematically investigated. Under optimal conditions, the limits of detection (LODs) were 72 and 44 ng L(-1) for Hg(2+) and MeHg(+) (as Hg) with online concentration factors of 12.5 and 12.1, respectively. The relative standard deviations (RSDs) for nine replicate determinations at 5 ng mL(-1) levels of mercury species were 2.7 and 2.0% for Hg(2+) and MeHg(+), respectively. The calibration graphs were linear with a correlation coefficient of 0.9902 in the range of 0.5-100 ng mL(-1) for Hg(2+) and 0.9976 in the range of 0.1-100 ng mL(-1) for MeHg(+), respectively. The developed method was successfully applied to the direct determination of MeHg(+) and Hg(2+) in seafood samples, and the recoveries for the spiked samples were in the range of 89.9-102.4% (MeHg(+)) and 87.0-104.6% (Hg(2+)), respectively. The method was validated by analyzing a certified reference material DORM-2 (dogfish muscle), and the determined values were in good agreement with certified values.
建立了一种在线微柱分离/预富集结合电感耦合等离子体发射光谱法（ICP - OES）测定海产品中痕量甲基汞（MeHg(+)）和无机汞（Hg(2+)）的简单有效方法。研究发现，Hg(2+)在pH 7.0至强酸性介质（6 mol L(-1) HCl）中可被YPA 4树脂定量吸附，而MeHg(+)仅在pH 1.0 - 7.0时被YPA 4微柱保留。因此，采用能从生物样品中释放汞形态的强酸性介质（约5 mol L(-1) HCl）直接将无机Hg(2+)与总汞分离，流出液调至pH 1.5后，其中的MeHg(+)被YPA 4柱保留。系统研究了酸度、样品流速和体积、洗脱液以及干扰离子对两种汞形态回收率的影响。在最佳条件下，Hg(2+)和MeHg(+)（以Hg计）的检出限（LOD）分别为72和44 ng L(-1)，在线浓缩因子分别为12.5和12.1。汞形态浓度为5 ng mL(-1)时，九次重复测定的Hg(2+)和MeHg(+)的相对标准偏差（RSD）分别为2.7%和2.0%。校准曲线呈线性，Hg(2+)在0.5 - 100 ng mL(-1)范围内相关系数为0.9902，MeHg(+)在0.1 - 100 ng mL(-1)范围内相关系数为0.9976。所建立的方法成功应用于海产品样品中MeHg(+)和Hg(2+)的直接测定，加标样品的回收率分别在89.9 - 102.4%（MeHg(+)）和87.0 - 104.6%（Hg(2+)）范围内。通过分析有证标准物质DORM - 2（鲨鱼肌肉）对该方法进行验证，测定值与标准值吻合良好。
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