Development and Validation of a Quantitative Method for Multiresidue Pesticides in Food Matrices Using the Agilent 6475 LC/TQ System

Significance of the Topic

The reliable detection and quantification of pesticide residues in food is critical for consumer safety, regulatory compliance and environmental protection. Multi-residue methods enable laboratories to monitor a wide variety of compounds across diverse matrices, ensuring adherence to maximum residue limits and supporting public health initiatives.

Objectives and Study Overview

This study reports the development and full validation of a high-throughput LC-MS/MS method for simultaneous quantification of 497 pesticides in wheat, olive oil and black tea. The method employs the Agilent 1290 Infinity II Bio LC system coupled with the new 6475 Triple Quadrupole LC/MS platform to achieve enhanced sensitivity, robustness and compliance with regulatory guidelines.

Instrumentation

• Agilent 1290 Infinity II Bio LC system:
   • 1290 Bio High-Speed Pump
   • 1290 Bio Multisampler with Cooler
   • 1290 Multicolumn Thermostat
  • Column: ZORBAX RRHD Eclipse Plus C18, 2.1 × 150 mm, 1.8 μm
  • Mobile phase A: 5 mM ammonium formate + 0.1% formic acid in water
  • Mobile phase B: 5 mM ammonium formate + 0.1% formic acid in methanol
• Agilent 6475 Triple Quadrupole LC/MS (AJS source):
   • Positive/negative polarity
   • Gas temperature: 200 °C; drying gas: 11 L/min
   • Sheath gas: 350 °C, flow 12 L/min; nebulizer gas: 35 psi
   • Capillary voltage: ±3500 V; cycle time: 500 ms; total MRMs: 1003; dynamic MRM acquisition

Methodology

Sample preparation followed QuEChERS EN protocols. Matrix-matched calibration curves (0.1–50 μg/L) corresponded to final levels of 0.5–250 μg/kg (wheat, tea) and 0.2–100 μg/kg (olive oil). The method exploited scheduled autotune, intelligent optimizer and iReflex for automated method development, expanding an existing 6470 LC/TQ library to 497 compounds.

Main Results and Discussion

• Linearity: 459 pesticides in wheat (92%), 465 in olive oil (94%) and 458 in tea (92%) achieved R² > 0.99.
  
• Sensitivity: LLOQ ≤10 μg/kg for 465 (94%) in wheat, 486 (98%) in olive oil and 466 (94%) in tea.
• Precision and accuracy: Consistently met acceptance criteria across nine calibration levels.
• Chromatographic performance: 1003 MRMs monitored within a 20-minute gradient with clear separation and average dwell times under 2 ms.
• Robustness: 300 replicate injections over five days yielded retention time RSD ≤0.41% and response RSD ≤5.2% for representative pesticides.

Benefits and Practical Applications

This platform offers high throughput analysis with minimal maintenance downtime, broad compound coverage and seamless transfer of existing MRM libraries. It supports compliance with 21 CFR Part 11 and Annex 11, making it suitable for regulatory, quality control and research laboratories tackling complex food matrices.

Future Trends and Applications

Anticipated developments include further automation of method optimization via AI-driven software, extension to additional challenging matrices, integration of reflexive reinjection strategies for trace-level monitoring, and expansion into environmental and forensic applications.

Conclusion

The validated method on the Agilent 1290 Infinity II Bio LC coupled with 6475 TQ MS demonstrates exceptional sensitivity, precision, linearity and robustness for multi-residue pesticide analysis in food. Its flexible, software-driven approach and regulatory compliance features position it as a powerful tool for modern analytical laboratories.

References

• MP 329 High-fidelity legacy-to-modern method transfer on a novel triple quadrupole LC/MS platform for large-output production labs.
• MP 327 An end-to-end software algorithm for LC/MS/MS method development, optimization, and QA/QC deployment.
• WP 493 Multi-residue Method Development Using Agilent 6475 LC/TQ System Implemented with Intelligent Optimization Software: Application to Forensic Drug Screening.