Multi-Residue Analysis of 210 Pesticides in Food Samples by Triple Quadrupole UHPLC-MS/MS

Importance of the topic

Modern agriculture relies heavily on pesticides to maintain crop yields and quality. However, residues of these chemicals in food can pose health risks, disrupt ecosystems and contaminate water resources. Regulatory agencies worldwide have established maximum residue limits (MRLs) to protect consumers, driving the need for sensitive, high-throughput multi-residue analytical methods.

Objectives and study overview

The study aimed to develop and validate a single ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS) method using a triple quadrupole instrument for quantifying 210 commonly encountered pesticides in fruit and vegetable matrices. Key goals included achieving low detection limits, robust repeatability and compliance with EU and international regulatory guidelines.

Methodology and instrumentation

Sample preparation followed a QuEChERS protocol to extract pesticides from dried fruit, lettuce and pear matrices into acetonitrile. A Shimadzu Nexera UHPLC system equipped with a Shim-pack XR-ODS III column (2.0 × 150 mm, 2.2 µm) was used. The optimized mobile phase consisted of water and methanol containing 5 mM ammonium formate and 0.01 % formic acid under a 16 min gradient at 0.4 mL/min. Injection band compression (performance-optimising injection sequence, POISe) with a 30 µL water plug improved peak shapes for early-eluting analytes. Detection employed a Shimadzu LCMS-8040 triple quadrupole with electrospray ionisation in positive/negative switching mode. Selected reaction monitoring transitions were optimised by automated flow injection analysis to maximize sensitivity and selectivity.

Main results and discussion

• Limits of detection (LODs) were below 0.01 mg/kg for all 210 pesticides; 90 % of compounds showed LODs <0.001 mg/kg (quantifier) and <0.002 mg/kg (qualifier).
• Calibration linearity was excellent (R² > 0.99) across 0.5–200 µg/kg in solvent and matrix-matched standards.
• Repeatability at the 0.01 mg/kg level was typically <5 % RSD for 92 % of analytes.
• Chromatographic resolution exceeded 1.0 for critical isomeric pairs, and POISe reduced early-eluting peak widths by up to 69 %.

Benefits and practical applications

This method enables routine screening of a broad pesticide panel at or below EU and Japanese default MRLs with minimal sample preparation steps. The short run time, low injection volume (2 µL) and reduced solvent consumption improve laboratory throughput and cost-effectiveness. The approach can be readily implemented in governmental, industrial and research laboratories for food safety and quality control.

Future trends and potential applications

• Extension to additional emerging contaminants and metabolites.
• Integration of fully automated sample preparation and data processing workflows.
• Adoption of high-resolution or hybrid mass analyzers for non-target screening.
• Development of green chemistry approaches using alternative solvents and sustainable protocols.
• Miniaturized or portable UHPLC-MS systems for on-site rapid testing.

Conclusion

The presented UHPLC-MS/MS method on the Shimadzu LCMS-8040 meets the stringent sensitivity, precision and throughput requirements for multi-residue pesticide analysis in food. Its robust performance and broad applicability support compliance with global food safety regulations and facilitate trade and consumer protection.

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