Successful Low Level Mercury Analysis

Importance of the Topic

Mercury is a highly toxic heavy metal used across industry and regulated in environmental and consumer products. Its accurate quantification at trace levels is essential for compliance and safety monitoring in water, food, pharmaceuticals and other matrices.

Objectives and Scope of the Article

This application note demonstrates how the Agilent 7700 Series ICP-MS enables routine detection of mercury at single-parts-per-trillion concentrations within standard multi-element analyses, overcoming traditional challenges in sample preparation, sensitivity and spectral interferences.

Methodology and Used Instrumentation

A stable mercury complex is formed by adding 0.5–1.0% HCl to samples and standards, preventing adsorption and volatility losses. Closed-vessel digestion ensures sample integrity. The plasma is optimized for maximum temperature to enhance Hg ionization (minimize CeO+/Ce+ ratio). A helium collision cell removes chloride-based polyatomic interferences in a single universal He mode, simplifying the removal of ArCl, CaCl, ClO and ClOH species.

Instrumentation

• Agilent 7700 Series ICP-MS
• Helium collision cell mode

Main Results and Discussion

The universal He mode effectively suppresses all Cl-based interferences, allowing inclusion of HCl in sample matrices without compromising measurements of V, Cr or As. Calibration curves for the 201Hg isotope demonstrate reliable detection down to low ppt levels with low background equivalent concentrations. Chemical stability tests confirm high recovery and consistent washout performance.

Benefits and Practical Applications of the Method

• Simultaneous multi-element and low-level mercury determination in a single run.
• Elimination of separate Hg analyzers and dedicated sample prep workflows.
• Enhanced sample throughput and laboratory productivity.
• Improved accuracy and stability through simple acid stabilization.

Future Trends and Applications

• Further refinement of collision/reaction cell technologies for universal interference removal.
• Integration with speciation techniques (e.g., GC-ICP-MS) for detailed mercury species analysis.
• Development of automated workflows and in-field portable ICP-MS systems.
• Expanding regulatory requirements driving lower detection limits and broader matrix compatibility.

Conclusion

The Agilent 7700 Series ICP-MS simplifies low-level mercury analysis by combining high plasma sensitivity and universal He collision mode, enabling routine ppt-level quantification within standard multi-element workflows. This approach enhances laboratory efficiency and data reliability for regulatory and research applications.

References

• Agilent Technologies. Application note: Successful Low Level Mercury Analysis using the Agilent 7700 Series ICP-MS.