Sensitive and Repeatable Analysis of Pesticides in QuEChERS Extracts with APGC-MS/MS

Importance of the topic

Pesticide residues in fruits and vegetables must be monitored at trace levels to comply with strict regulatory MRLs. The diversity of over 1000 active ingredients and complex matrices requires analytical methods that deliver high sensitivity, accuracy, and robustness, enabling food safety and public health assurance.

Objectives and study overview

This work evaluates the use of atmospheric pressure gas chromatography coupled with tandem mass spectrometry (APGC-MS/MS) on a Waters Xevo TQ-S system to achieve sensitive and repeatable multi-residue pesticide analysis in QuEChERS extracts of strawberry, pear, and spinach.

Methodology and used instrumentation

• Sample preparation: DisQuE QuEChERS CEN protocol (CEN 15662) with acetonitrile extraction.
• Gas chromatography: Agilent 7890A GC with DB-5MS column (30 m×0.25 mm×0.25 µm); helium carrier gas (1.2 mL/min); temperature program from 70 °C to 300 °C over 30 min.
• Mass spectrometry: Waters Xevo TQ-S with interchangeable APGC source; operated in positive MRM mode; source conditions optimized for [M+H]+ ionization via added water vapor.
• Data processing: TargetLynx Application Manager for automated MRM processing.

Main results and discussion

Twenty GC-amenable pesticides exhibited limits of detection between 0.01 and 0.5 ng/mL, with linear calibration ranges (0.05–50 ng/mL) achieving R2 > 0.99 and residuals < 15%. Spike recoveries at 1 µg/kg showed accuracy within ± 5% and RSDs below 5% across strawberry, pear, and spinach matrices. APGC’s soft ionization significantly enhanced molecular ion abundance compared to traditional EI, enabling more selective and sensitive MRM transitions.

Benefits and practical applications of the method

• Single MS platform for both GC and LC analytes, streamlining workflows.
• Enhanced sensitivity and selectivity through soft APGC ionization.
• Compliance with stringent regulatory MRLs and improved throughput.
• Reduced matrix interferences and instrument maintenance via sample dilution.

Future trends and applications

Adoption of APGC-MS/MS is expected to expand across food and environmental laboratories, with potential for high-throughput screening, integration of broader analyte panels, and advanced data analytics, further improving pesticide monitoring capabilities.

Conclusion

APGC-MS/MS on the Xevo TQ-S platform delivers a sensitive, accurate, and reproducible approach for multi-residue pesticide determination in QuEChERS extracts, overcoming limitations of conventional EI-GC-MS/MS and meeting current regulatory demands.

References

• Portolés T, Cherta L, Beltran J, Hernandez F. J Chromatogr A. 2012;1260:183.