Accurately Identify and Quantify One Hundred Pesticides in a Single GC Run

Importance of the Topic

Pesticide residue monitoring is essential for ensuring food safety and regulatory compliance. As global agriculture relies on hundreds of chemical agents to protect crops, laboratories require robust analytical methods capable of detecting multiple compounds in a single run with high sensitivity and throughput.

Objectives and Study Overview

This study compared traditional time-segmented multiple reaction monitoring (TS-MRM) with dynamic MRM (dMRM) acquisition for the simultaneous analysis of 195 pesticides. The goal was to assess method development time, sensitivity, quantitative performance, and flexibility across diverse food matrices.

Methodology and Sample Preparation

Eight sample types (yellow onion, navel orange, organic honey, cucumber, jasmine rice, baby spinach, loose leaf tea, extra virgin olive oil) underwent QuEChERS extraction followed by matrix-specific dispersive SPE cleanup. Two GC/MS/MS methods (40 and 20 min) were executed under constant flow conditions. TS-MRM and dMRM methods were developed using MassHunter software, optimizing retention time windows and dwell times to maintain a constant MS cycle time and sampling rate.

Used Instrumentation

• Agilent 7890B Gas Chromatograph with multimode inlet
• Agilent 7693B Autosampler
• Agilent 7010A Triple Quadrupole GC/MS
• Agilent J&W HP-5ms Ultra Inert columns (15 m × 0.25 mm, 0.25 µm) with midcolumn backflush

Main Results and Discussion

dMRM reduced the number of concurrent transitions, enabling longer dwell times and maintaining ~5 scans/sec across peaks. Performance metrics showed: 90% of compounds with calibration R² ≥ 0.990, repeatability (%RSD) ≤ 30%, and LOQs ≤1.5 pg/µL for most analytes. Chromatograms in various matrices demonstrated comparable or improved signal-to-noise ratios and peak shapes in dMRM vs TS-MRM.

Benefits and Practical Applications

• Accelerated method development (5–10 min)
• Ease of adding or removing analytes without manual time-segment editing
• Enhanced sensitivity through optimized dwell times
• High-throughput capability for complex multi-residue analysis

Future Trends and Potential Uses

Advances may include automated retention time locking, AI-driven optimization of MS parameters, expansion to additional compound classes, integration with real-time quality control, and coupling with multidimensional separations to further increase throughput and selectivity.

Conclusion

Dynamic MRM acquisition in GC/MS/MS offers a flexible and efficient alternative to traditional time-segment methods for multi-pesticide analysis. It delivers equivalent or superior quantitative performance while streamlining method setup and supporting high-throughput demands.

References

1. Anastassiades M. et al. AOAC Int. 2003;86:412–431.
2. Lehotay SJ et al. AOAC Int. 2005;88:615–629.
3. Westland J, Stevens J. Application note, Agilent Technologies; Pub. 5991-7303EN, 2016.