Analysis of 9 Haloacetic Acids in Tap Water Using the LCMS-8040 Triple Quadrupole Mass Spectrometer

Importance of the Topic

Haloacetic acids are common disinfection by-products formed during chlorination of drinking water. Three of these compounds—monochloroacetic acid, dichloroacetic acid and trichloroacetic acid—are regulated under tap water quality standards due to their potential health risks. Reliable, sensitive and high-throughput methods for quantifying these and related haloacetic acids are essential for routine water quality monitoring and regulatory compliance.

Objectives and Overview

This study demonstrates a direct liquid chromatography–tandem mass spectrometry (LC-MS/MS) method for simultaneous determination of nine haloacetic acids in tap water using the Shimadzu LCMS-8040 triple quadrupole instrument. The goals were to eliminate lengthy solvent extraction and derivatization steps, achieve low-level quantification, and validate performance in real and spiked tap water samples.

Methodology and Instrumentation

The analysis employed a CAPCELL PAK MGIII column (150 mm × 4.6 mm, 3 μm) with a gradient from 5 percent to 100 percent methanol in 0.2 percent formic acid over 38 minutes. Electrospray ionization in negative mode was used, with multiple reaction monitoring (MRM) transitions optimized for each analyte. Key instrument settings included a 50 μL injection volume, 0.2 mL/min flow rate, a probe voltage of −3.5 kV, and column temperature of 30 °C.

• Analytes: Monochloroacetic acid, Dichloroacetic acid, Trichloroacetic acid, Monobromoacetic acid, Bromochloroacetic acid, Dibromoacetic acid, Bromodichloroacetic acid, Chlorodibromoacetic acid, Tribromoacetic acid
• Instrument: Shimadzu LCMS-8040 triple quadrupole mass spectrometer
• MRM transitions optimized for sensitivity and selectivity

Main Results and Discussion

Calibration was linear over 0.001–0.2 mg/L for all nine acids, with correlation coefficients above 0.995 and peak area repeatability below 5 percent at 0.001 mg/L. Direct injection of tap water without cleanup produced recoveries between 90 and 110 percent. No significant matrix interferences were observed, confirming the robustness of the method for regulatory and quality-control applications.

Benefits and Practical Application

The direct LC-MS/MS approach significantly reduces sample preparation time by removing solvent extraction and derivatization steps. High sensitivity and precision enable reliable compliance testing at or below regulatory limits. The method is suitable for routine monitoring in municipal and industrial water analysis laboratories.

Future Trends and Applications

Emerging trends include automated online sampling and real-time monitoring of disinfection by-products, extension of the method to additional polar and nonpolar by-products, and integration with high-resolution mass spectrometry for suspect screening. Advances in microfluidics and ambient ionization may further streamline water quality analysis workflows.

Conclusion

The LCMS-8040–based LC-MS/MS method offers a fast, accurate and solvent-free protocol for simultaneous quantification of nine haloacetic acids in tap water. Its high throughput, low detection limits and excellent recoveries support its adoption for routine water quality monitoring and regulatory compliance.

Reference

1. Maiko Tahara, Naoki Sugimoto, Reiji Kubota, Tetsuji Nishimura: Establishment of Direct Quantitation Method of Haloacetic Acids in Tap Water Using Liquid Chromatograph/Mass Spectrometer, Journal of the Japan Water Works Association, 907, 18-22 (2010)
2. Maiko Tahara, Reiji Kubota, Norihiro Kobayashi, Taku Tsukamoto, Naoki Sugimoto, Tetsuji Nishimura: Verification of Quantitative Accuracy of the LC/MS/MS and LC/MS Analysis of Haloacetic Acids in Tap Water in the Presence of Anions, Journal of the Japan Water Works Association, 931, 20-27 (2012)