Robustness, reproducibility, reliability with best-in-class sensitivity: Increased confidence in targeted quantitation of pesticides in food matrices

Significance of the Topic

The accurate quantitation of pesticide residues in food is critical for consumer safety and regulatory compliance. Low maximum residue limits (MRLs) set by European regulations demand sensitive, reliable, and reproducible analytical methods. Implementing a robust workflow ensures routine food control laboratories can confidently screen complex matrices while meeting stringent quality criteria.

Objectives and Study Overview

This study presents the development and validation of a comprehensive LC-MS/MS method for the determination of over 250 pesticides in food matrices at concentrations below EU MRLs. The workflow integrates QuEChERS extraction, high-throughput UHPLC separation, and triple quadrupole mass spectrometry with automated data processing to achieve rapid, precise, and accurate quantitation.

Methodology and Instrumentation

Sample preparation follows the EN 15662 QuEChERS protocol: homogenization of 10 g of sample, extraction with acetonitrile, shaking, centrifugation, and direct transfer of supernatant into vials without further cleanup. Chromatographic separation is performed on a 2.1×100 mm Accucore aQ column with a 15-minute gradient using water and methanol mobile phases containing ammonium formate and formic acid. Mass spectrometric detection employs timed-SRM acquisition with polarity switching and optimized dwell times for high throughput.

Instrumentation

• Vanquish Flex Binary UHPLC system
• TSQ Quantis triple quadrupole mass spectrometer
• TraceFinder software for acquisition and data processing
• QuEChERS extraction kits
• Accucore aQ C18 Polar Endcapped column (100×2.1 mm, 2.6 µm)

Key Results and Discussion

The optimized method achieved clear chromatographic separation of 250+ pesticides in 15 minutes with 1 µL injection volumes. Timed-SRM reduced concurrent transitions, enabling short dwell times (as low as 2.5 ms) while maintaining peak integrity and sensitivity at 1 ppb. Comparative testing demonstrated the TSQ Quantis outperformed its predecessor in peak area (3×–10× increase) and signal stability. Long-term robustness was confirmed with consistent atrazine response (4.5% RSD) over 400 matrix injections without maintenance.

Benefits and Practical Applications

• High throughput: 15 min analysis and minimal sample cleanup.
• Exceptional sensitivity: LOQs below 10 µg/kg for diverse pesticides.
• Cost-effective workflow: no additional SPE steps required.
• Regulatory compliance: validated to EU guidelines for accuracy, precision, and selectivity.
• Reproducibility: stable performance across hundreds of injections.

Future Trends and Opportunities

Advances may include further miniaturization of sample prep, integration of high-resolution MS for non-target screening, and application of AI-driven data processing to streamline method development. Expanding compound libraries and adapting to emerging pesticide chemistries will enhance food safety monitoring globally.

Conclusion

The described LC-MS/MS workflow offers a robust, reproducible, and highly sensitive solution for multi-residue pesticide analysis in food matrices. It meets stringent EU regulatory requirements while reducing analysis time and complexity, making it well suited for routine QA/QC laboratories.

References

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4. European Commission. SANCO/11945/2015 Guidance document on analytical quality control and method validation procedures for pesticides residue analysis in food and feed. 2015.
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