Quantitative analysis of halogenated acetic acids in water using IC-MS/MS

Significance of the Topic

The formation of halogenated acetic acids (HAAs) during water disinfection raises health concerns due to their persistence and potential toxicity. Accurate monitoring of these byproducts is crucial to ensure potable water safety and compliance with regulatory limits.

Objectives and Study Overview

This work presents the development of a rapid and sensitive ion chromatography tandem mass spectrometry (IC-MS/MS) method to quantify a range of mono- and multi-halogenated acetic acids in water samples, meeting the EU Drinking Water Directive requirements.

Used Instrumentation

• Metrohm 940 Professional IC Vario One SeS/PP/HPG system
• Metrosep A Supp 7 – 250/4.0 separation column
• Metrohm Inline Ultrafiltration unit for automated particle removal
• 858 Professional Sample Processor with MiPT for precise injection and calibration
• SCIEX QTRAP 6500+ mass spectrometer with IonDrive Turbo V source

Methodology

• Direct injection of untreated water samples with inline filtration
• Gradient elution using NaOH/carbonate buffer with acetonitrile modifier at 0.8 mL/min
• Suppressor module to reduce salt-induced background and enhance sensitivity
• Negative-ion MRM acquisition with optimized transitions and 50 ms dwell times

Main Results and Discussion

The method achieved complete separation of five regulated HAAs and additional analytes in a 25-minute run. Limits of detection between 0.02 and 0.2 µg/L were obtained, with calibration linearity (r² ≥ 0.998) over four orders of magnitude. Direct analysis of tap and bottled water, including spikes at 2 µg/L, demonstrated reliable quantification and minimal matrix effects.

Benefits and Practical Applications

• Minimal sample preparation and high automation reduce labor and variability
• Sensitivity and robustness fulfill EU directive criteria for water monitoring
• Suitable for routine QA/QC in drinking water treatment plants and environmental labs

Future Trends and Opportunities

• Extension to emerging ionic contaminants such as fluorinated and iodinated acids
• Integration of high-throughput sample preparation and AI-driven data analysis workflows
• Development of faster gradients and novel suppressor technologies for increased throughput

Conclusion

The IC-MS/MS approach delivers a fast, reliable, and automated solution for HAA analysis in water. Its high sensitivity, ease of use, and compliance with regulatory standards make it ideal for a wide range of analytical settings focusing on water quality assurance.

Reference

1. Rook JJ. Formation of haloforms during chlorination of natural waters. J Water Treat Exam. 23:234–243 (1974).
2. Pelwa MJ et al. Cytotoxicity and genotoxicity of haloacetic acids. Environ Mol Mutagen. 51(8-9):871–878 (2010).
3. World Health Organization. Guidelines for Drinking-water Quality, 3rd ed., Vol. 1 (2008).
4. Behringer D et al. Persistent degradation products of halogenated refrigerants. Umweltbundesamt (2021).
5. Ellis DA et al. Thermolysis of fluoropolymers as a source of halogenated organic acids. Nature. 412(6844):321–324 (2001).
6. Directive (EU) 2020/2184 on water quality for human consumption (2020).