Selective organomercury determination by ICP-MS made easy

A fast and cost-effective procedure based on Inductively Coupled Plasma -Mass Spectrometry (ICP-MS) for the selective determination of methylmercury (MeHg) is proposed and validated for fish tissue analysis. Selectivity for MeHg is achieved by simply inserting a strong anion exchange resin to block inorganic mercury as negatively charged chloride species, leaving MeHg unretained. The procedure features a 15 min extraction time followed by a 100 s analysis time achieving a limit of detection of 1.6 mg kg(-1) on solid samples. The effect of the solution composition and inorganic mercury concentration were extensively studied to fully assess the selectivity of the procedure: Hg(II):MeHg ratios up to 50 are tolerated and cause systematic errors lower than 15%. The entire procedure was successfully validated by standard reference material from the marine food web, namely fish muscle and liver plus zooplankton. The method was finally applied to the detection of MeHg in the marine trophic web of Djibouti (Gulf of Aden): atrophic magnification factor of 13.5 proved the high risk associated with the biomagnification of methylmercury. (c) 2022 Elsevier B.V. All rights reserved.

Automated summary

A fast and cost-effective procedure based on ICP-MS was proposed for the selective determination of methylmercury in fish tissue. The procedure achieved selectivity for methylmercury by inserting a strong anion exchange resin to block inorganic mercury. It featured a short extraction time and analysis time with a low limit of detection. The procedure was validated using standard reference materials and successfully applied to detecting methylmercury in the marine trophic web of Djibouti, revealing a high risk associated with biomagnification of methylmercury.