Selective organomercury determination by ICP-MS made easy

Area of Science:

• Environmental Chemistry
• Analytical Chemistry

Background:

• Mercury is a toxic heavy metal.
• Methylmercury (MeHg) biomagnifies in aquatic ecosystems.
• Accurate MeHg determination in food webs is crucial for risk assessment.

Purpose of the Study:

• To develop and validate a fast, cost-effective, and selective method for methylmercury determination in fish tissue.
• To assess the selectivity and performance of the proposed analytical procedure.
• To investigate methylmercury levels and biomagnification in a marine food web.

Main Methods:

• Inductively Coupled Plasma - Mass Spectrometry (ICP-MS) coupled with anion exchange chromatography.
• Selective extraction of methylmercury from fish tissue using a strong anion exchange resin.
• Validation using certified reference materials (fish muscle, liver, zooplankton).

Main Results:

• The method provides selective MeHg determination with a limit of detection of 1.6 μg kg⁻¹.
• High tolerance for inorganic mercury (Hg(II):MeHg ratios up to 50) with minimal error (<15%).
• Trophic magnification factor of 13.5 observed in the Djibouti marine food web, indicating significant MeHg biomagnification.

Conclusions:

• The developed ICP-MS procedure is a rapid and reliable tool for selective MeHg analysis in fish.
• The study confirms the substantial risk of methylmercury biomagnification in marine environments.
• The findings underscore the importance of monitoring MeHg in seafood for human and ecosystem health.