IC-ICP/MS – with Metrohm

Importance of the Topic

Ion chromatography coupled with inductively coupled plasma mass spectrometry provides species-specific separation and ultra-low detection limits for trace elements. This combined approach is essential for accurate toxicity assessment and regulatory compliance such as distinguishing chromium III from chromium VI or quantifying bromate according to EPA method 321.8.

Objectives and Study Overview

This work demonstrates the integration of Metrohm ion chromatography with ICP-MS detection. It outlines analytical challenges addressed by IC-ICP/MS, highlights arsenic speciation in rice as a representative application, and emphasizes benefits for quality control, environmental monitoring, and industrial analysis.

Methodology and Instrumentation

A Metrosep Carb 2 column (250/2.0) was employed with a gradient of ammonium bicarbonate and ammonium nitrate buffers at pH 8.6. Chromatography was conducted at 40 °C, 0.2 mL/min flow, and 20 µL injection volume. An ICP-MS operated at 1550 W plasma power with gas flows of 17 L/min (plasma), 1 L/min (auxiliary), and 0.94 L/min (nebulizer) provided element specific detection with 0.1 s integration time.

Used Instrumentation

• Metrohm ion chromatograph with Metrosep Carb 2 column 250/2.0
• Eluent A: 4 mmol/L ammonium bicarbonate
• Eluent B: 4 mmol/L ammonium bicarbonate and 40 mmol/L ammonium nitrate
• ICP-MS detector with 1550 W plasma power and specified gas flow settings

Main Results and Discussion

The IC-ICP/MS method achieved clear separation of arsenic species and significantly lower detection limits compared to conventional detectors. Element-specific detection minimized matrix interferences and improved quantification accuracy. Inline sample preparation and tailored chromatographic conditions further enhanced method robustness and reproducibility.

Benefits and Practical Applications

• Accurate speciation for reliable toxicity assessment
• Reduced matrix effects through separation and cleanup
• Enhanced sensitivity by coupling high-sensitivity ICP-MS
• Unified software control with comprehensive audit trails
• Compatibility with ICP-MS instruments from any manufacturer

Future Trends and Opportunities

Advancements in automated inline sample preparation techniques and suppressor technology will further streamline workflows. Integration with advanced data management systems and machine learning could optimize method development and peak assignment. Expansion of IC-ICP/MS to new environmental, food safety, and biomedical matrices promises broader analytical applications.

Conclusion

IC-ICP/MS coupling using Metrohm systems delivers a powerful analytical platform combining selectivity and sensitivity for trace element speciation. Its robust hardware, software integration, and compliance features support precise risk assessment in environmental, industrial, and regulatory contexts.

References

1. Use of the IC-ICP-MS and IC-ESI-MS coupling for elemental species analysis of arsenic Bachelor thesis by Lukas Bischof Marburg 2017
2. Metrohm white paper WP-008 2018