Lin Liang-Yen, Chang Lan-Fang, Jiang Shiuh-Jen
Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan.
J Agric Food Chem. 2008 Aug 27;56(16):6868-72. doi: 10.1021/jf801241w. Epub 2008 Jul 23.
A simple and rapid procedure for the separation and determination of inorganic, methyl, and ethyl mercury compounds was described using liquid chromatography (LC) followed by vapor generation inductively coupled plasma-mass spectrometry (VG-ICP-MS). Well resolved chromatograms were obtained within 5 min by reversed-phase liquid chromatography with a C8 column as the stationary phase and a pH 4.7 solution containing 0.5% v/v 2-mercaptoethanol and 5% v/v methanol as the mobile phase. The separated mercury compounds were converted to mercury vapors by an in situ nebulizer/vapor generation system for their introduction into ICP. The concentrations of NaBH4 and HNO3 required for vapor generation were also optimized. The method was applied for the speciation of mercury in reference materials NIST SRM 1568a Rice Flour and NIST SRM 1567a Wheat Flour and also rice flour and wheat flour samples purchased locally. The accuracy of the procedure was verified by analyzing the certified reference material NRCC DOLT-3 Dogfish Liver for methyl mercury. Precision between sample replicates was better than 13% for all the determinations. The detection limits of the mercury compounds studied were in the range 0.003-0.006 ng Hg mL(-1) in the injected solutions, which correspond to 0.02-0.06 ng g(-1) in original flour samples. A microwave-assisted extraction procedure was adopted for the extraction of mercury compounds from rice flour, wheat flour, and fish samples using a mobile phase solution.
描述了一种简单快速的方法，用于分离和测定无机汞、甲基汞和乙基汞化合物，该方法采用液相色谱（LC），随后进行蒸汽发生电感耦合等离子体质谱（VG-ICP-MS）分析。使用C8柱作为固定相，以含有0.5%（v/v）2-巯基乙醇和5%（v/v）甲醇的pH 4.7溶液作为流动相，通过反相液相色谱在5分钟内获得了分离良好的色谱图。分离出的汞化合物通过原位雾化器/蒸汽发生系统转化为汞蒸汽，以便引入ICP中。还对蒸汽发生所需的硼氢化钠和硝酸的浓度进行了优化。该方法应用于参考物质NIST SRM 1568a米粉和NIST SRM 1567a小麦粉以及当地购买的米粉和小麦粉样品中汞的形态分析。通过分析认证参考物质NRCC DOLT-3角鲨鱼肝中的甲基汞来验证该方法的准确性。所有测定中，样品重复之间的精密度优于13%。所研究的汞化合物在注入溶液中的检测限为0.003 - 0.006 ng Hg mL(-1)，这相当于原始面粉样品中0.02 - 0.06 ng g(-1)。采用微波辅助萃取程序，使用流动相溶液从米粉、小麦粉和鱼类样品中萃取汞化合物。
