Quantitative Analysis of Nine Haloacetic Acids in Tap Water Using LCMS™ - 8050RX

Importance of the Topic

The presence of haloacetic acids (HAAs) in drinking water is a global concern due to potential health risks associated with disinfection by-products. Regulatory agencies in Japan and the EU have set stringent limits for several HAAs to ensure water safety. Rapid, sensitive, and reliable analytical methods are essential for routine monitoring and compliance.

Objectives and Overview of the Study

This application note aims to demonstrate a quantitative method for nine HAAs in tap water using Shimadzu’s LCMS-8050RX. The goals were to achieve a short analysis cycle, simple sample pretreatment, and robust validation performance in terms of linearity, accuracy, and precision.

Used Instrumentation

• LCMS-8050RX Triple Quadrupole Mass Spectrometer (Shimadzu)
• Nexera X3 HPLC System
• Shim-pack GIST-HP C18 Column (150 mm × 3.0 mm I.D., 3 µm)

Methodology

Sample pretreatment involved dechlorination of tap water using sodium ascorbate. The LC method employed 0.2 % formic acid in water (A) and methanol (B) with a gradient from 1 % to 100 % B over 7 minutes, returning to initial conditions by 11 minutes, for a total run time of 15 minutes. The flow rate was 0.5 mL/min at 40 °C, with 20 µL injection volume. Mass spectrometry was performed in negative ESI mode, monitoring multiple reaction monitoring (MRM) transitions specific to each HAA.

Results and Discussion

Calibration was linear between 2 and 30 µg/L for each HAA, with coefficients of determination (r²) exceeding 0.999. At the 2 µg/L level, accuracy ranged from 80 % to 120 %, and repeatability (RSD) was below 10 %. Spike-and-recovery tests in tap water confirmed method performance with recoveries between 88 % and 111.5 % and RSD below 10 % for all analytes.

Benefits and Practical Application of the Method

• Simultaneous quantitation of nine HAAs in a single 15 minute run
• Low detection limits (2 µg/L) suitable for regulatory requirements
• Minimal sample preparation through simple dechlorination
• Robust linearity, accuracy, and precision compliant with validation guidelines

Future Trends and Possibilities

Potential extensions include adaptation to other water matrices, incorporation of high-throughput autosamplers, and integration with automated data processing using machine learning algorithms. Further development may focus on miniaturized or portable LC-MS platforms for on-site monitoring.

Conclusion

The LCMS-8050RX method provides a fast, sensitive, and reliable approach for the quantitative determination of nine haloacetic acids in tap water, meeting stringent regulatory standards for water quality monitoring.

References

• Ministerial Ordinance Concerning Water Quality Standards (Ministry of Health, Labour and Welfare Ordinance No. 101, 2003; No. 29, 2015)
• Directive (EU) 2020/2184 on the quality of water intended for human consumption