Analysis of Haloacetic Acids in Drinking Water by IC-MS/MS

Importance of the topic

Haloacetic acids are disinfection by-products formed when chlorine reacts with organic matter in drinking water. Five of these compounds are regulated by the US EPA due to potential health risks including cancer. Comprehensive monitoring of all nine known haloacetic acids supports regulatory compliance and protects public health.

Objectives and study overview

The aim was to develop a simple, rapid, and sensitive ion chromatography–tandem mass spectrometry method for direct analysis of nine haloacetic acids in drinking water without derivatization or extraction.

Methodology

Water samples were injected directly onto an anion-exchange column using an electrolytically generated hydroxide gradient. An inline self-regenerating suppressor converted hydroxide to water before mass spectrometry. A matrix diversion valve removed high salt fractions to waste while acetonitrile make-up flow improved desolvation.

Main results and discussion

All nine haloacetic acids were baseline separated from common inorganic anions and quantified with excellent linearity from 0.25 to 20 ppb. Method detection limits ranged from 0.097 to 0.459 µg/L, comparable to EPA method 552.2. Recoveries in a simulated high-salt matrix exceeded 90 % for most analytes. Dibromochloroacetic acid exhibited lower ionization efficiency and sensitivity to column temperature, highlighting the need for strict control of analytical conditions.

Benefits and practical applications

• Eliminates derivatization and extensive sample preparation
• Reduces matrix interference for robust quantitation
• Enables rapid, high-throughput monitoring in water treatment and QA/QC laboratories
• Meets or exceeds regulatory performance for drinking water analysis

Future trends and potential applications

Emerging high-resolution mass spectrometry could enhance selectivity further. Portable IC-MS systems may allow onsite monitoring. Advances in suppressor technology and automation will expand applicability to other disinfection by-products and complex matrices.

Conclusion

The IC-MS/MS approach provides a streamlined, sensitive, and regulatory-compliant method for comprehensive analysis of haloacetic acids in drinking water, minimizing sample handling while ensuring accurate results.

References

• US EPA Method 552.1 Determination of Haloacetic Acids by Ion Exchange and GC ECD, 1992
• US EPA Method 552.2 Determination of Haloacetic Acids by Liquid–Liquid Extraction and GC ECD, 1995
• US EPA Method 552.3 Determination of Haloacetic Acids by Liquid Microextraction and GC ECD, 2003
• US EPA Microbial Health Effects Tables, 2002
• Slignsby R Saini C Pohl C Jack R Measurement of Haloacetic Acids Using IC-MS/MS, Pittsburgh Conference, 2008