High Speed Analysis of Pesticides Listed in 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

The presence of pesticide residues in drinking water poses significant health and environmental concerns Regulatory agencies continually update standards to ensure safety In March 2018 the Japanese Ministry of Health expanded Appendix Method 20-2 to include 181 target pesticides requiring efficient high throughput analysis

Objectives and Study Overview

The study aimed to develop and validate a rapid simultaneous analysis method using a triple quadrupole LC/MS/MS system to detect 181 pesticides listed in Appendix Method 20-2 within a 25 minute run time Based on Japanese drinking water inspection guidelines the method performance was evaluated for 152 of these compounds excluding 29 deemed referential

Methodology and Instrumentation

The analytical workflow combined solid phase extraction with triple quadrupole LC/MS/MS using a metal free ODS column to mitigate adsorption issues The mobile phase gradient employed ammonium acetate in water and methanol at a flow rate of 0.25 mL per minute Key mass spectrometer conditions included electrospray ionization in positive and negative modes high desolvation and interface temperatures and optimized gas flows

Used Instrumentation

• Shimadzu LCMS-8050 Triple Quadrupole Mass Spectrometer
• InertSustain AQ-C18 PEEK metal free column 50 mm × 2.1 mm i d 1.9 μm
• Ammonium acetate aqueous and methanolic mobile phases
• Standard solid phase extraction apparatus

Results and Discussion

The total ion current chromatogram demonstrated baseline separation of 181 pesticides within 25 minutes Method detection limits reached one hundredth of regulatory target values for all compounds Calibration curves showed excellent linearity with correlation coefficients above 0.997 for newly added pesticides Spike recovery studies in dechlorinated tap water yielded recoveries between 80 and 113 percent with relative standard deviations below 20 percent across 152 validated analytes

Benefits and Practical Applications

• High throughput screening of a wide pesticide panel in routine water quality control
• Rapid compliance with updated regulatory requirements
• Minimal method development due to simultaneous analysis capabilities
• Enhanced sensitivity enabling trace level quantitation

Future Trends and Opportunities

Advances in high resolution mass spectrometry and data processing may enable suspect and non target screening complementing targeted methods Integration with laboratory automation and cloud based informatics can further improve throughput Digital reporting and real time monitoring systems represent emerging opportunities to enhance water quality surveillance

Conclusion

The optimized triple quadrupole LC/MS/MS method meets current Japanese water quality requirements by delivering rapid accurate quantitation of 181 pesticides The validated performance for 152 compounds demonstrates robustness precision and sensitivity suitable for routine environmental monitoring

Reference

Shimadzu Corporation Application note LAAN-A-LM-E143 High Speed Analysis of Pesticides in Appendix Method 20-2 June 2018