Analysis of Haloacetic Acids, Bromate, and Dalapon in Natural Waters by Ion Chromatography Tandem Mass Spectrometry

Significance of the Topic

Water disinfection processes are essential for public health but generate by-products such as haloacetic acids (HAAs), bromate, and dalapon that pose carcinogenic and toxicological risks. Rapid, sensitive, and accurate monitoring of these compounds at low µg/L levels is critical for regulatory compliance and water quality assurance.

Objectives and Study Overview

This study presents a direct injection ion chromatography-tandem mass spectrometry (IC-MS/MS) method to analyze 13 HAAs, bromate, and dalapon in natural waters. The goal was to reduce analysis time by more than half compared to USEPA Method 557, expand the list of target analytes to include four iodinated HAAs, and achieve low reporting limits without laborious sample preparation.

Methodology and Used Instrumentation

The method employs a Metrohm 850 Professional IC system with a Supp 7 column (250 × 4.0 mm) and a 100 µL direct water injection using a carbonate/hydroxide linear gradient eluent. Detection is performed on an Agilent 6490 Triple Quadrupole LC/MS with Jet Stream dual ESI in negative mode and multiple reaction monitoring (MRM). Quantification uses isotopically labeled internal standards and external calibration for select analytes.

Main Results and Discussion

• Run time was 27 minutes, compared to 55 minutes for Method 557, while maintaining resolution and column lifespan.
• Statistical method reporting limits ranged from 0.03 to 1.3 µg/L for all analytes.
• Seven-point calibration curves (0.5–50 µg/L) yielded R² > 0.995 for each compound.
• Matrix spike recoveries in drinking and surface water (10 µg/L) were 77.5–124.6% with RSDs below 12.5%.
• Real-world samples revealed multiple HAAs at low µg/L concentrations; none exceeded the 60 µg/L HAA5 MCL, and bromate/dalapon were not detected.

Practical Benefits and Applications

This IC-MS/MS approach eliminates derivatization and extraction, cutting labor and error sources. Faster analysis improves laboratory throughput for QA/QC in municipal water utilities, environmental monitoring, and research settings.

Future Trends and Potential Applications

Advances may include automated sample handling, expanded target lists for emerging DBPs, use of high-resolution MS for structural elucidation, and greener eluents. Integration with remote monitoring platforms and real-time analysis could further enhance water quality management.

Conclusion

The validated IC-MS/MS method offers a robust, fast, and sensitive tool for comprehensive monitoring of HAAs, bromate, and dalapon in natural waters, supporting regulatory compliance and public health protection.

References

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