Analysis of 764 Pesticides in Tomato Using an Agilent 6495D Triple Quadrupole LC/MS System

Significance of the Topic

Pesticide residues in food pose critical health and environmental risks. Regulatory bodies set stringent maximum residue levels (MRLs) in the low parts-per-billion range, driving the need for sensitive, high-throughput analytical methods. The simultaneous screening of hundreds of compounds in complex matrices such as tomato extract demands robust, rapid workflows to ensure food safety and compliance.

Study Objectives and Overview

This study aimed to develop and validate a comprehensive LC–MS/MS workflow for the determination of 764 pesticides in QuEChERS-extracted tomato samples. By transferring a previously established multiple reaction monitoring (MRM) method to the latest Agilent 6495D triple quadrupole system, the work sought to demonstrate improvements in sensitivity, speed, and reliability for routine pesticide residue analysis.

Methodology and Instrumentation

• Sample Preparation: Tomatoes were homogenized and subjected to a QuEChERS extraction using Agilent EN kits. Ten grams of sample were mixed with 10 mL acetonitrile, shaken, salted-out, centrifuged, and the supernatant directly analyzed.
• Calibration: Matrix-matched standards were prepared at 10 levels (0.1–100 µg/L) from two intermediate mixes, with serial dilutions in tomato matrix.

Used Instrumentation

• Agilent 1290 Infinity III LC system with ZORBAX RRHD Eclipse Plus C18 column (2.1 × 150 mm, 1.8 µm).
• Agilent 6495D triple quadrupole mass spectrometer with Jet Stream electrospray source and tunable 4th-generation iFunnel.
• Dynamic multiple reaction monitoring (dMRM) mode with up to 1,590 transitions and compound-specific iFunnel settings.

Results and Discussion

• Method Transfer: The existing MRM method for 764 pesticides was smoothly migrated to the 6495D, adjusting only gas-flow parameters.
• Chromatography: Achieved baseline separation of all analytes within a 20 min gradient (95–100% organic) at 0.4 mL/min, with peak widths of 8–12 s.
• Acquisition Speed: With a 500 ms cycle time, up to 151 concurrent dMRMs delivered dwell times as low as 0.9 ms, yielding over 15 data points per peak even at high transition density.
• iFunnel Tuning: Compound-specific settings (Standard, Fragile, Large Molecule) improved sensitivity for labile analytes by up to an order of magnitude.
• Linearity and Sensitivity: Matrix-matched calibration curves (0.1–100 ng/mL) showed R2 ≥ 0.99 for all targets. At 0.1 ng/mL, signal-to-noise ratios exceeded 30 for representative compounds, compared to <10 without iFunnel.

Benefits and Practical Applications

• Enhanced Sensitivity: iFunnel technology and dynamic MRM increased detection power for trace-level pesticides.
• High Throughput: Short run times and high acquisition speed enable large-panel screening in routine QA/QC labs.
• Robustness: Stable performance in complex food matrices supports reliable monitoring under production conditions.
• Method Transferability: Easy migration from previous LC/TQ platforms facilitates technology upgrades without extensive redevelopment.

Future Trends and Potential Uses

• Panel Expansion: Further increase in the number of monitored compounds through enhanced computing and multiplexing.
• Automation: Integration with online sample prep and data-processing pipelines for real-time decision support.
• High-Resolution Complementarity: Coupling with HRMS platforms to confirm unknowns and perform non-targeted screening.
• Regulatory Adaptation: Rapid method updates to address emerging contaminants and evolving MRL guidelines.

Conclusion

The Agilent 1290 Infinity III/6495D LC–TQ system offers a significant advancement for multi-residue pesticide analysis in food matrices. Combining rapid dynamic MRM, compound-specific iFunnel tuning, and exceptional sensitivity, the workflow meets demanding regulatory standards and supports high-throughput, routine pesticide monitoring.

Reference

1. Regulation (EC) No. 396/2005 on Maximum Residue Levels of Pesticides in Food and Feed.
2. Kornas, P.; et al. Quantitation of 764 Pesticide Residues in Tomato by LC/MS According to SANTE 11312/2021 Guidelines. Agilent Technologies, 2023.
3. Agilent Technologies. Method Protocol for Multi-Residue Pesticides in Food Using 6470 TQ, 2022.
4. SANTE/11312/2021: Analytical Quality Control and Method Validation Procedures for Pesticide Residues Analysis in Food and Feed.