Screening for More Than 740 Pesticide Residues in Food Using an Agilent GC/Q-TOF and an Exact Mass Pesticide Library

Importance of the topic

Ensuring food safety requires reliable methods to screen for hundreds of possible pesticide residues in fruits and vegetables. Global trade and varying maximum residue limits (MRLs) demand broad multiresidue approaches that can detect contaminants at low levels without extensive calibration.

Objectives and study overview

This work evaluates a high resolution Agilent 7200 GC/Q-TOF method combined with an Exact Mass Pesticides Personal Compound Database and Library to screen QuEChERS extracts of six organically grown produce samples spiked with 93 pesticides at 10 and 100 ng/mL levels. Two midcolumn backflushing GC methods were compared: a 20-minute 5×15 configuration and a 40.5-minute 15×15 configuration.

Použitá instrumentace

• Agilent 7890B Gas Chromatograph with 7693A autosampler
• Agilent 7200A Quadrupole Time-of-Flight Mass Spectrometer
• Agilent DB-5 columns (5 m×0.25 mm and 15 m×0.25 mm)
• Agilent QuEChERS EN Extraction and Dispersive SPE kits
• Robot Coupe Blender, Geno Grinder, Vortexer and Centrifuge

Použitá metodika

Produce samples were homogenized, extracted by the EN QuEChERS method, and cleaned by dispersive SPE. Extracts were spiked at 10 and 100 ng/mL with nine pesticide standard mixes. Data were acquired in full scan high resolution TOF EI mode and processed with MassHunter Qualitative Analysis using the All Ions workflow and the Exact Mass Pesticides PCDL. Retention times were locked to reference compounds, and midcolumn backflushing removed matrix interferences.

Main results and discussion

The 5×15 method identified on average 97.3 % of pesticides at 10 ng/mL and 99.6 % at 100 ng/mL. The longer 15×15 method yielded similar results: 97.1 % at 10 ng/mL and 99.8 % at 100 ng/mL. Mass accuracy of the molecular ion was better than 2 ppm for signals with S/N > 10 and averaged 5.7 ppm for lower abundance ions. Full scan data allowed retrospective compound screening.

Benefits and practical applications

• High throughput screening for >700 pesticides without individual calibration
• Robust detection at or below default 10 ppb MRLs
• Midcolumn backflush reduces matrix buildup and extends column life
• Retrospective analysis enables postacquisition review for additional compounds

Future trends and applications

• Expansion of exact mass libraries to cover emerging pesticides
• Integration with advanced deconvolution and machine learning tools
• Hybrid HRAM screening combining GC/Q-TOF and LC/HRAM workflows
• Automated reporting and compliance monitoring in QA/QC labs

Conclusion

The Agilent GC/Q-TOF All Ions screening approach with an Exact Mass pesticide library and rapid midcolumn backflush offers a fast, selective, and sensitive solution for monitoring hundreds of pesticide residues in food matrices with high mass accuracy and flexible data review.

Reference

1. US EPA. Indexes to Part 180 Tolerance Information for Pesticide Chemicals in Food and Feed Commodities.
2. European Commission. Maximum Residue Levels.
3. New Zealand Ministry of Primary Industries. Pesticide Maximum Residue Limit (MRL) legislation around the world.
4. Codex Alimentarius. CODEX Pesticides Residues in Food Online Database. FAO/WHO.
5. Mastovska K, Wylie PL. Evaluation of a new column backflushing setup in GC-MS/MS analysis of pesticide residues in dietary supplements. J Chromatogr A. 2012;1265:155–164.
6. Mastovska K. Rugged GC/MS/MS Pesticide Residue Analysis Fulfilling USDA PDP Requirements. Agilent Technologies; 5991-1054EN.
7. Chen Y, et al. Multiresidue pesticide analysis of dried botanical dietary supplements using automated d-SPE QuEChERS and LC-MS/MS. J Agric Food Chem. 2012;60(40):9991–9999.
8. Banerjee K, et al. Multiresidue determination of 375 organic contaminants by GC-MS/MS with semi-quantification. J Chromatogr A. 2012;1270:283–295.
9. Satpathya G, Tyagi YK, Gupta RK. Optimized microwave-assisted QuEChERS and GC-MS with deconvolution for pesticide residues. Food Chem. 2011;127(3):1300–1308.
10. Mezcua M, et al. Simultaneous GC-Q-TOF screening and targeted approach for pesticides in produce. J AOAC Int. 2009;92(6):1790–1806.
11. EN 15662. Foods of plant origin – determination of pesticide residues by GC-MS and/or LC-MS/MS following QuEChERS–d-SPE cleanup.