Marine Environmental Studies Laboratory, International Atomic Energy Agency, 4 Quai Antoine 1(er), MC, 98000, Monaco; Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, 02-089, Warsaw, Poland.
Marine Environmental Studies Laboratory, International Atomic Energy Agency, 4 Quai Antoine 1(er), MC, 98000, Monaco.
Talanta. 2020 Sep 1;217:121113. doi: 10.1016/j.talanta.2020.121113. Epub 2020 May 1.
Species-specific isotope dilution inductively coupled plasma quadrupole mass spectrometry reference method and high-performance liquid chromatography were applied for simultaneous determination of mercury species in marine samples. Different extraction protocols for mercury species were tested and evaluated. It was found that after exposure to microwave energy the inorganic mercury (iHg) and methyl mercury (MeHg) can be completely extracted from marine biota sample by 4.5 mol L HCl as well as by 3.0 mol L HNO and further separated with HPLC. The obtained results for iHg and MeHg in the IAEA-461 certified reference material (CRM) clam Gafrarium tumidum biota sample were as follow: (341 ± 21) μg kg or (338 ± 15) μg kg and (61.3 ± 2.2) μg kg (recovery of (98.4 ± 3.6) %) or (61.1 ± 2.8) μg kg (recovery of (98.1 ± 4.6) %), respectively when diluted HCl or HNO were applied in the extraction step. However, these protocols are not applicable to marine sediment samples, where the iHg is the predominant form. Therefore, one selective extraction procedure for MeHg from sediment was applied to make possible its separation and quantification. This procedure consisted of series of subsequent extraction steps at room temperature: first with a mixture of HSO/KBr/CuSO, next with organic solvent dichloromethane and as a final step one back-extraction with NaSO solution. The combination of the selective extraction with the ID calibration approach was found to be an efficient way for the simultaneous determination and separation of both MeHg and iHg species in one chromatographic run. The proposed procedure was successfully used for the determination of mercury species in the IAEA-405 sediment CRM and further applied for the simultaneous measurements of iHg and MeHg in a candidate CRM - the IAEA-475 sediment sample. The determined mass fractions were (30.1 ± 1.6) μg kg and (196 ± 8) ng kg for iHg and MeHg, respectively. The difference between obtained in this study results and those from the reference IAEA-475 values was 1.5% and further validated the developed in this study analytical methodology. To the best of our knowledge, this selective procedure for MeHg extraction was never used before for the simultaneous quantification of mercury species in marine sediment.
采用物种特异性同位素稀释电感耦合等离子体质谱（ID-ICP-MS）参考方法和高效液相色谱法（HPLC）同时测定海洋样品中的汞形态。测试和评估了不同的汞形态提取方案。结果发现，经微波能量处理后，4.5 mol/L HCl 和 3.0 mol/L HNO 可以完全提取海洋生物样品中的无机汞（iHg）和甲基汞（MeHg），并通过 HPLC 进一步分离。在 IAEA-461 有证参考物质（CRM）贻贝 Gafrarium tumidum 生物样品中，iHg 和 MeHg 的测定结果如下：（341±21）μg/kg 或（338±15）μg/kg 和（61.3±2.2）μg/kg（回收率为（98.4±3.6）%）或（61.1±2.8）μg/kg（回收率为（98.1±4.6）%），当在提取步骤中使用稀释 HCl 或 HNO 时。然而，这些方案不适用于海洋沉积物样品，其中 iHg 是主要形态。因此，应用了一种从沉积物中选择性提取 MeHg 的方法，使其能够进行分离和定量。该程序包括一系列在室温下的后续提取步骤：首先使用 HSO/KBr/CuSO 的混合物，然后使用有机溶剂二氯甲烷，最后用 NaSO 溶液进行反萃取。发现选择性提取与 ID 校准方法相结合是一种有效的方法，可在一次色谱运行中同时测定和分离 MeHg 和 iHg 形态。所提出的程序已成功用于测定 IAEA-405 沉积物 CRM 中的汞形态，并进一步应用于 IAEA-475 沉积物候选 CRM 中 iHg 和 MeHg 的同时测量。测定的质量分数分别为 iHg 为（30.1±1.6）μg/kg 和 MeHg 为（196±8）ng/kg。本研究结果与参考 IAEA-475 值之间的差异为 1.5%，进一步验证了本研究中开发的分析方法。据我们所知，这种用于 MeHg 提取的选择性方法以前从未用于同时定量海洋沉积物中的汞形态。
