Accurate Quantitation of Pesticides and PCB's in Grape and Onion Extracts using High Resolution GC-Orbitrap Mass Spectrometry

Importance of the Topic

The accurate quantitation of pesticides and PCBs in fruits and vegetables is critical for food safety, regulatory compliance, and public health.

Objectives and Overview of the Study

This work evaluates the quantitative performance of an Exactive GC Orbitrap mass spectrometer for simultaneous analysis of 88 pesticides and 7 PCBs in grape and onion matrices.

Methodology and Used Instrumentation

Grape and onion samples were extracted using a modified miniLuke protocol involving acetone, dichloromethane, petroleum ether, and sodium sulfate, followed by solvent exchange to ethyl acetate.
Calibration curves spanning 1–200 µg/kg were prepared in matrix.
Blind-spiked samples (0.5–100 µg/kg) assessed accuracy.

Used Instrumentation:

• TriPlus RSH autosampler
• Thermo Scientific TRACE 1310 GC with TraceGOLD TG-5SilMS column (30 m × 0.25 mm × 0.25 µm)
• Exactive GC Orbitrap MS (full-scan, 60 000 FWHM at m/z 200, mass range 50–700 Da, electron ionization at 70 eV)
• TraceFinder software for data acquisition and quantitative processing

Results and Discussion

Limits of detection for 92 of 95 analytes were ≤ 2 ng/mL (three analytes at 5 ng/mL), all below EU MRLs.
Matrix-matched calibration yielded linearity R² > 0.99 and response factor RSD% < 20% over 1–200 µg/kg.
Blind-spike recoveries ranged from 82% to 106%, demonstrating accurate quantitation.
Full-scan data facilitated retrospective ion extraction (±5 ppm) and flexible method optimization.

Benefits and Practical Applications

• Sensitive, robust full-scan screening without predefined targets
• Streamlined method setup and maintenance with integrated guard column
• High-throughput compliance monitoring for laboratories and QA/QC environments
• Capability for retrospective analysis of additional compounds

Future Trends and Opportunities

The integration of high-resolution MS with advanced data analytics and AI will enable broader non-target screening.
Expansion to other food matrices and coupling with LC-HRMS can further enhance multi-residue workflows.
Automated data review and cloud-based platforms may improve laboratory efficiency and traceability.

Conclusion

The Exactive GC Orbitrap system provides reliable, high-resolution quantitation of pesticides and PCBs in complex matrices, meeting stringent regulatory criteria and supporting robust food safety monitoring.

References

1. European Commission. Guidelines on MRLs. 2015.
2. European Commission. Regulation (EC) No. 396/2005.
3. SANTE/11945/2015 Guidance on analytical quality control.
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6. Thermo Fisher Scientific Application Note 10448. 2016.
7. Thermo Fisher Scientific Application Note 10509. 2016.
8. Thermo Fisher Scientific Application Note 10541. 2017.