Speciation Analysis of Mercury in Seafood by LC-ICP-MS

Significance of the Topic

Mercury contamination in seafood represents a critical public health concern due to the high toxicity of organic mercury species, particularly methylmercury. Accurate assessment of mercury forms is essential for complete risk evaluation and regulatory compliance.

Objectives and Study Overview

This study aimed to develop and validate a liquid chromatography inductively coupled plasma mass spectrometry method for mercury speciation in seafood by coupling an ICPMS-2040/2050 with a Nexera XS inert system. Additionally, the automatic dilution function of the autosampler was evaluated to streamline calibration and improve analytical efficiency.

Methodology and Instrumentation

Samples of commercial tuna were prepared using the FDA Elemental Analysis Manual method 4.81. After homogenization and spiking for recovery tests, mercury species were extracted with a 1 percent L-cysteine-HCl solution at 60 °C for two hours. Extracts were filtered and introduced into the LC-ICP-MS system.

Used Instrumentation

• Shimadzu ICPMS-2040/2050
• Shimadzu Nexera XS inert HPLC system
• LabSolutions ICPMS TRM software for integrated control of sample injection and data analysis

Results and Discussion

Chromatographic separation successfully resolved inorganic mercury, methylmercury, and ethylmercury at 0.5 µg/L. Calibration curves exhibited excellent linearity with correlation coefficients above 0.999. Limits of detection for each species met low µg/L requirements. Automatic dilution produced accurate standards with repeatability confirmed across multiple preparations. Analysis of spiked tuna extract yielded recoveries of 102 percent for methylmercury and 105 percent for total mercury, demonstrating method robustness.

Benefits and Practical Applications of the Method

• High sensitivity and selectivity for mercury species
• Streamlined workflow with unified software control
• Automated calibration reduces manual errors
• Compliance with FDA guidelines for seafood analysis

Future Trends and Potential Applications

Continued advancements may include coupling with high resolution mass analyzers, miniaturized and portable LC-ICP-MS platforms for field screening, enhanced data processing with machine learning, and further automation in sample preparation and dilution.

Conclusion

The LC-ICP-MS method with an integrated Nexera XS inert system offers reliable speciation analysis of mercury in seafood, achieving high accuracy, sensitivity, and compliance with regulatory standards, supporting improved risk assessments in food safety.

References

• Naka K, Jiang Y, Iwata N, Gruszecka D. Speciation Analysis of Mercury in Seafood by LC-ICP-MS. Shimadzu Corporation; 2023.