Analysis of Pesticides Added to Appendix Method 20-2 for the Complementary Items for Water Quality Management in Japan Using a Triple Quadrupole LC/MS/MS

Significance of the Topic

Liquid chromatography–tandem mass spectrometry (LC–MS/MS) is a pivotal tool in monitoring trace pesticide residues in drinking water, ensuring environmental safety and regulatory compliance.

Objectives and Study Overview

• To incorporate 113 newly regulated pesticides into Japan’s Appendix Method 20-2.
• To validate quantitative performance down to one-hundredth of the target concentration or lower.

Methodology and Instrumentation

The study utilized a Shimadzu LCMS-8050 triple quadrupole system with electrospray ionization (ESI) in positive and negative modes. Chromatographic separation employed a metal-free L-column2 ODS (150 × 2.0 mm, 3 μm) with a gradient of 5 mmol/L ammonium acetate in water and methanol. Key conditions included 0.2 mL/min flow rate, 40 °C column temperature, 50 μL injection volume, and source/interface temperatures of 300 °C/250 °C.

Main Results and Discussion

• Calibration curves for all 113 added pesticides exhibited excellent linearity (R² > 0.999).
• Limits of quantification reached as low as 0.003 μg/L for the most sensitive analytes.
• Spike-and-recovery tests in dechlorinated tap water (n=5) showed recoveries between 80 % and 120 % with relative standard deviations below 18 % across 99 pesticides.
• Newly introduced, low-concentration, and revised-limit pesticides were reliably quantified at one-hundredth of their regulatory thresholds.

Contributions and Practical Applications

This validated LC–MS/MS approach enables high-throughput and sensitive monitoring of a broad spectrum of pesticide residues in drinking water. It supports regulatory compliance, enhances quality assurance and quality control processes, and streamlines routine environmental analysis.

Future Trends and Applications

• Integration with automated sample preparation and software-driven data analysis for increased laboratory throughput.
• Extension to emerging contaminants, metabolites, and degradation products.
• Application of ultrahigh-performance LC and high-resolution mass spectrometry for expanded analyte coverage and improved selectivity.

Conclusion

The expanded Appendix Method 20-2 LC–MS/MS protocol achieves robust, sensitive, and reproducible quantification of 113 additional pesticides, thereby strengthening water quality surveillance and meeting stricter regulatory requirements.

References

No formal literature references were provided in the original document.