Quantitation of 764 Pesticide Residues in Tomato by LC/MS according to SANTE 11312/2021 Guidelines

Importance of the topic

Routine screening and quantitation of pesticide residues in food commodities is essential for ensuring public health, complying with regulatory MRLs, and managing environmental risks. Methods capable of detecting hundreds of analytes rapidly and reliably support high-throughput laboratory operations and consistent enforcement of safety standards.

Objectives and study overview

This application note describes the development and verification of a comprehensive LC/MS/MS workflow for quantifying 764 pesticide residues in tomato. The method was designed to meet European SANTE 11312/2021 guidelines, achieve fast turnaround with a 20-minute LC runtime, and simplify sample preparation using QuEChERS extraction.

Methodology and instrumentation

Sample preparation relied on a QuEChERS EN extraction kit with a simple acetonitrile extraction and no further cleanup. Matrix-matched calibration standards (0.5–100 µg/L) were prepared in tomato extract to correct matrix effects. Chromatographic separation was performed on an Agilent 1290 Infinity II LC with a ZORBAX RRHD Eclipse Plus C18 column (2.1 × 150 mm, 1.8 µm) using a 20-minute gradient at 0.4 mL/min. Detection employed an Agilent 6470 triple quadrupole LC/MS in dynamic MRM mode with fast polarity switching. The method included 1,590 optimized MRM transitions drawn from the Agilent Pesticide Dynamic MRM Database.

Main results and discussion

• Linearity: Over 98% of compounds exhibited R² ≥0.99 across eight calibration levels (0.5–100 µg/L).
• Instrument LOD: More than 99% of analytes achieved S/N ≥10 at ≤10 µg/L; 92% maintained S/N ≥10 at 1 µg/L in tomato extract.
• Matrix effects: At 10 µg/L, 72% of pesticides showed insignificant suppression or enhancement (<20%), with the remainder balanced between enhancement and suppression.
• Precision (RSDr): 96% of compounds met RSDr ≤20% in six technical replicates at 10 µg/kg.
• Recovery: Mean recoveries fell between 40% and 120% for 95% of targets; most compounds were between 70% and 120% recovery.

Benefits and practical applications of the method

This workflow supports high-throughput pesticide monitoring in food testing laboratories by combining rapid sample preparation, robust chromatographic separation, and sensitive, selective MS detection. It reduces operating costs and turnaround times while ensuring compliance with regulatory standards for hundreds of target residues.

Future trends and applications

Integration of larger dynamic MRM libraries, advances in high-resolution mass spectrometry, and automated data processing will further streamline multi-residue workflows. Expanded applicability to other complex matrices and incorporation of isotopically labeled standards can enhance quantitation accuracy and method robustness.

Conclusion

A validated 20-minute LC/MS/MS method for 764 pesticide residues in tomato meets SANTE 11312/2021 performance criteria for linearity, sensitivity, recovery, and precision. The use of QuEChERS extraction and dynamic MRM acquisition delivers a fast, reliable solution for routine regulatory screening.

References

• SANTE 11312/2021: 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, 2022.
• Zou A, et al. Comprehensive LC/MS/MS Workflow of Pesticide Residues in Food Using the Agilent 6470 Triple Quadrupole LC/MS System. Agilent Technologies Application Note 5994-2370EN, 2020.