MULTIRESIDUE PESTICIDE ANALYSIS IN FRUITAND VEGETABLE COMMODITIES USING BOTH UPLC AND APGC ON A SINGLE MASS SPECTROMETER PLATFORM

Importance of Topic

The comprehensive monitoring of pesticide residues in fruits and vegetables is critical for ensuring food safety and regulatory compliance. With hundreds of approved pesticides in use, analytical methods must achieve high throughput, sensitivity, and reliability to enforce maximum residue limits (MRLs) and to detect unauthorized compounds.

Objectives and Study Overview

This study demonstrates a streamlined workflow for multiresidue pesticide analysis using both ultra performance liquid chromatography (UPLC) and gas chromatography with atmospheric pressure chemical ionization (APGC) on a single tandem quadrupole mass spectrometer. The approach aims to minimize instrument switching time, maximize compound coverage, and meet SANTE/11945/2015 validation criteria for sensitivity, precision, and linearity.

Methodology and Instrumentation

Sample Preparation and Cleanup:

• QuEChERS extraction followed by dispersive SPE cleanup with MgSO4, PSA, and GCB tailored to each matrix (celery, lemon, corn, kale).

Chromatographic and Mass Spectrometric Conditions:

• UPLC-MS/MS: ACQUITY UPLC H-Class system with BEH C18 column; mobile phases water and methanol (10 mM ammonium acetate); electrospray ionization in positive mode.
• APGC-MS/MS: Agilent 7890A GC with Rxi-5MS column; proton transfer ionization; rapid switching from UPLC inlet enabled by a Universal Source on Xevo TQ-S micro.
• MRM transitions: ~200 pesticides per method with ≥2 transitions each; acquisition speed sufficient to obtain ≥12 data points per peak.

Main Results and Discussion

Sensitivity and Linearity:

• Matrix-matched calibration over 0.001–0.050 mg/kg; UPLC responses linear (R² ≥ 0.995) and APGC responses fitted quadratically.

Detection and Precision:

• At 0.010 mg/kg spiking level, >99% of pesticides were detected by at least one method; many compounds were detectable at 0.001 mg/kg.
• Repeatability was excellent: >90% of detected pesticides exhibited RSDs < 10% (except APGC kale analysis where >80% met this criterion).
• Ion ratio deviations in matrix remained within ±30% tolerance.

Instrument Performance:

• The Xevo TQ-S micro’s fast scanning capability maintained peak quality while monitoring extensive MRM lists.
• Switching between UPLC and APGC in under 30 minutes increased laboratory efficiency without sacrificing sensitivity.

Benefits and Practical Applications

This unified platform enables regulatory, industry, and research laboratories to:

• Perform broad-spectrum pesticide residue screening with minimal method downtime.
• Achieve regulatory MRLs for diverse compound classes with high confidence in data quality.
• Simplify method development and maintenance using integrated databases (QuanPedia).

Future Trends and Applications

Advances may include:

• Expansion of compound libraries to include emerging pesticides and transformation products.
• Integration of high-resolution mass spectrometry for non-target screening in the same workflow.
• Automated data processing pipelines that leverage machine learning for anomaly detection and rapid reporting.

Conclusion

The combined UPLC-MS/MS and APGC-MS/MS approach on a single Xevo TQ-S micro platform offers a robust, efficient solution for multiresidue pesticide analysis in fruit and vegetable commodities. The method meets stringent validation criteria, simplifies laboratory workflows, and ensures compliance with global residue regulations.

References

1. D. Shah, E. McCall, G. Cleland. Single LC-MS/MS Method for Confirmation and Quantification of Over 400 Pesticides in a Complex Matrix Without Compromising Data Quality. Waters Application Note 720005559EN, January 2016.
2. Kovalczuk T., Jech M., Poustka J., Hajslova J. UPLC-MS/MS: A Novel Challenge in Multiresidue Pesticide Analysis in Food. Analytica Chimica Acta, 577, 2006.
3. Tienstra M., Portoles T., Hernandez F., Mol J.G.J. Fast Gas Chromatographic Residue Analysis in Animal Feed Using Split Injection and Atmospheric Pressure Chemical Ionisation Tandem Mass Spectrometry. J. Chromatogr. A, 1422, 2015.
4. Cherta L., Portoles T., Beltran J., Pitarch E., Mol J.G.J., Hernandez F. Application of Gas Chromatography–Mass Spectrometry with Atmospheric Pressure Chemical Ionisation for Multiclass Pesticides in Fruits and Vegetables. J. Chromatogr. A, 1314, 2013.
5. European Commission. Guidance Document on Analytical Quality Control and Method Validation Procedures for Pesticide Residues Analysis in Food and Feed (SANTE/11945/2015). 2015.