Comprehensive LC/MS/MS Workflow of Pesticide Residues in Food Using the Agilent 6470 Triple Quadrupole LC/MS System

Significance of the Topic

Pesticide residue monitoring in food products is critical for consumer safety and regulatory compliance. Multiresidue analysis methods must address diverse chemical structures and food matrices, including high water, starch, and lipid content. Advances in liquid chromatography–tandem mass spectrometry (LC–MS/MS) enable sensitive, selective, and high-throughput screening of hundreds of pesticides in a single run.

Objectives and Study Overview

This work aimed to develop and validate a streamlined LC/MS/MS workflow for quantifying 510 pesticide residues across three representative food matrices (tomato, wheat, and olive oil). Method goals included broad compound coverage, compliance with SANTE/12682/2019 performance criteria, and applicability to routine high-throughput laboratory operations.

Methodology and Instrumentation

Sample Preparation:

• Tomato and wheat: QuEChERS EN extraction followed by universal dSPE cleanup.
• Olive oil: QuEChERS extraction plus Agilent Captiva EMR—Lipid cleanup using a positive-pressure manifold.

Chromatography and Mass Spectrometry:

• LC: Agilent 1290 Infinity II with ZORBAX RRHD Eclipse Plus C18 column (2.1×150 mm, 1.8 µm), 20-min gradient (5–100% MeOH), 0.4 mL/min flow.
• MS/MS: Agilent 6470 triple quadrupole with Jet Stream ESI in dynamic MRM mode, fast polarity switching, >1,000 transitions in a single run, cycle time 500 ms.

Calibration and Quality Control:

• Matrix-matched standards from 1–100 µg/L; internal QC at 1, 5, and 10 µg/kg in each matrix.
• Instrument LOD defined at S/N≥3, workflow LOQ at S/N≥10 following full sample preparation.

Main Results and Discussion

Linearity and Sensitivity:

• >95% of compounds showed calibration R²≥0.99 over LOQ–50/100 µg/L.
• Instrument LODs and workflow LOQs met regulatory guidelines, with robust detection across matrices.

Recovery and Precision:

• Mean recoveries at 10 µg/kg: 92% of pesticides in tomato, 82% in wheat, 86% in olive oil fell within 40–120% recovery.
• Repeatability (RSDr) and intralaboratory reproducibility (RSDiR) for 90% of analytes were ≤20%.

Matrix Effects and Robustness:

• Matrix effects at 10 µg/L were insignificant (70–95% of targets) after matrix-matched calibration.
• Over 48 hours of continuous injections, peak responses for representative pesticides remained stable (RSD <3.5%).

Benefits and Practical Applications of the Method

This comprehensive workflow offers:

• High throughput analysis of >500 pesticides in a single 20-min LC/MS run.
• Reliable performance across diverse food matrices (high water, starch, oil).
• Ease of implementation using Agilent Pesticide Dynamic MRM Database and standard sample kits.

Laboratories can adopt this protocol for routine monitoring, compliance testing, and research applications in food safety and quality control.

Future Trends and Potential Applications

Emerging directions include:

• Extension to additional food matrices (dairy, spices, processed foods).
• Integration with high-resolution MS for unknown screening and non-targeted analysis.
• Automation of sample preparation and data processing for enhanced throughput.

Further expansion of curated MRM libraries will support evolving regulatory requirements and new pesticide chemistries.

Conclusion

The presented LC–MS/MS workflow demonstrates high sensitivity, accuracy, and reproducibility for multiresidue pesticide analysis in diverse food matrices. Conformance with SANTE/12682/2019 criteria and the use of streamlined sample preparation kits render it suitable for routine high-throughput testing in food safety laboratories.

References

• SANTE/12682/2019: Analytical quality control and method validation procedures for pesticide residues analysis in food and feed.
• Quantitative Analysis of Multi-Residue Pesticides in Food Matrices Using Agilent 6470 Triple Quadrupole LC/MS System – Method Protocol, 2020.
• Agilent pesticide standards and dynamic MRM database documentation.