Pesticide Analysis in Food and Beverages Application Compendium

Significance of Pesticide Screening in Food Safety

Ensuring that fruits, vegetables, cereals and feeds meet regulatory maximum residue limits (MRLs) for pesticides is essential to protect public health. Modern sample preparation techniques such as QuEChERS yield complex extracts that require highly selective, sensitive and high‐throughput analysis to reliably detect trace pesticide residues against diverse and challenging matrices.

Study Objectives and Overview

This study evaluates the performance of a full‐scan high‐resolution GC–Orbitrap mass spectrometer platform for broad‐scope pesticide screening. The goal is to demonstrate:

• Detection and confident identification of >180 GC‐amenable pesticides in a single analysis,
• Sensitivity at or below typical MRLs (<10 ppb),
• Robust screening in complex matrices (wheat, horse feed, leek),
• Ability to re‐interrogate data retrospectively for unanticipated compounds.

Methodology and Instrumentation

Sample Extraction

• QuEChERS with acetate buffer and acetonitrile extraction.
• Centrifugation, salt‐out partitioning, and cleanup to yield 0.5–1 g/mL extracts.

Chromatography

• Thermo Scientific TRACE 1310 GC with TraceGOLD TG-5SilMS 15 m × 0.25 mm × 0.25 µm capillary column.
• Fast oven program (40 °C to 300 °C in 17 min total cycle).

Mass Spectrometry

• Thermo Scientific Q Exactive GC (quadrupole–Orbitrap) in full‐scan EI mode.
• Resolving power up to 120 000 FWHM and mass accuracy <2 ppm.
• Data acquired at 60 000 FWHM (m/z 200), scan range 50–500 Da.

Data Processing

• TraceFinder software for automated screening using retention time, accurate mass, isotopic fit and fragment confirmation.

Main Results and Discussion

– All 55 target pesticides spiked at 10 ppb in wheat, feed and leek were detected with sub‐ppm mass errors.
– Sixty‐five percent of pesticides detected at 0.5–2.5 ppb in wheat, well below typical MRLs.
– A minimum resolving power of 60 000 is required to separate isobaric interferences (e.g., chlorpropham vs. matrix ions), avoiding false negatives.
– Fast GC–Orbitrap acquisition yields >10 mass spectral points across 1–2 s peaks, ensuring reliable quantitation.
– Screening traffic‐light reports in TraceFinder enable rapid pass/fail decision making and detailed review of suspect positives.

Benefits and Practical Applications

– Comprehensive, non‐targeted full‐scan acquisition covers hundreds of analytes in a single run without method re‐optimization.
– High mass resolution and accuracy enhance specificity and reduce false positives/negatives in complex matrices.
– Retrospective data mining capability allows discovery of new or unexpected contaminants post acquisition.
– Rapid throughput (up to 84 samples/day) and automated data processing increase laboratory efficiency and reduce cost per sample.

Future Trends and Opportunities

– Expansion of accurate‐mass libraries to include suspect and non‐target screening for environmental and food contaminants.
– Integration of artificial‐intelligence‐driven workflows for automated compound identification and risk assessment.
– Further miniaturization and automation of sample preparation to streamline end‐to‐end pesticide monitoring.

Conclusion

The combination of QuEChERS sample preparation with full‐scan high‐resolution GC–Orbitrap mass spectrometry provides a powerful, future‐proof approach for broad‐scope pesticide screening. High resolving power and sub‐ppm accuracy enable reliable detection of trace residues in complex food and feed matrices, meeting regulatory requirements while offering flexibility for retrospective analysis.

References

• European Commission Decision 2002/657/EC on performance of analytical methods.
• AOAC Official Method 2007.01: QuEChERS for pesticide residues in foods (Lehotay et al.).
• Thermo Scientific Q Exactive GC Application Note, 2021.