Simultaneous speciation analysis of mercury in marine origin samples by high performance liquid chromatography and species - specific isotope dilution inductively coupled plasma mass spectrometry

This peer-reviewed academic paper presents a comprehensive analytical methodology for the simultaneous determination of inorganic mercury (iHg) and methylmercury (MeHg) species in diverse marine samples, including biota and sediments. The study employed a species-specific isotope dilution inductively coupled plasma quadrupole mass spectrometry (SS ID ICP-QMS) method coupled with high-performance liquid chromatography (HPLC). The primary objective was to develop and validate robust extraction protocols suitable for different marine matrices, ensuring accurate and precise quantification of mercury species. For marine biota samples, the research demonstrated that both iHg and MeHg could be effectively extracted using diluted hydrochloric acid (4.5 mol L⁻¹ HCl) or nitric acid (3.0 mol L⁻¹ HNO₃) following microwave digestion, with subsequent HPLC separation. In contrast, marine sediment samples, characterized by a predominance of iHg, required a selective extraction procedure for MeHg involving a series of steps with H₂SO₄/KBr/CuSO₄, dichloromethane, and Na₂S₂O₃ solution. The combination of this selective extraction with the ID calibration approach proved highly efficient for simultaneous determination in a single chromatographic run. The developed procedure was successfully applied to certified reference materials (IAEA-461 clam biota, IAEA-405 sediment CRM) and a candidate CRM (IAEA-475 sediment sample), yielding results with high accuracy and low uncertainty, thereby validating its applicability for environmental monitoring and certification processes.

This peer-reviewed academic paper presents a comprehensive analytical methodology for the simultaneous determination of inorganic mercury (iHg) and methylmercury (MeHg) species in diverse marine samples, including biota and sediments. The study employed a species-specific isotope dilution inductively coupled plasma quadrupole mass spectrometry (SS ID ICP-QMS) method coupled with high-performance liquid chromatography (HPLC). The primary objective was to develop and validate robust extraction protocols suitable for different marine matrices, ensuring accurate and precise quantification of mercury species. For marine biota samples, the research demonstrated that both iHg and MeHg could be effectively extracted using diluted hydrochloric acid (4.5 mol L⁻¹ HCl) or nitric acid (3.0 mol L⁻¹ HNO₃) following microwave digestion, with subsequent HPLC separation. In contrast, marine sediment samples, characterized by a predominance of iHg, required a selective extraction procedure for MeHg involving a series of steps with H₂SO₄/KBr/CuSO₄, dichloromethane, and Na₂S₂O₃ solution. The combination of this selective extraction with the ID calibration approach proved highly efficient for simultaneous determination in a single chromatographic run. The developed procedure was successfully applied to certified reference materials (IAEA-461 clam biota, IAEA-405 sediment CRM) and a candidate CRM (IAEA-475 sediment sample), yielding results with high accuracy and low uncertainty, thereby validating its applicability for environmental monitoring and certification processes. Research Background and Significance Mercury contamination in marine environments poses significant ecological and health risks due to its bioaccumulation and toxicity, especially in the form of methylmercury (MeHg), a neur