EVALUATING ALTERNATIVE AND SIMPLIFIED CLEANUP OF FOODSTUFFS FOR GC-MS/MS DETERMINATION OF PESTICIDES

Importance of the Topic

Determination of pesticide residues in complex food matrices such as edible oils and produce is critical for ensuring food safety and regulatory compliance. Complex matrices require effective cleanup to protect analytical instruments and deliver reliable results.

Study Objectives and Overview

This study aims to evaluate and simplify sample cleanup strategies for the analysis of over 150 pesticides in olive oil, fruits, vegetables, and cereals. Two methods—involving acetonitrile extraction with either SPE cleanup or freeze-out defatting—were compared to traditional hexane extraction and GPC cleanup. The same SPE pass-through was further assessed on QuEChERS extracts of various produce.

Methodology and Instrumentation

Sample Preparation Methods:

1. Method 1: Acetonitrile extraction, freeze-out defatting, and SPE pass-through using Oasis PRiME HLB Plus.
2. Method 2: Similar extraction with additional freeze-out step replacing nonpolar solvents.

QuEChERS Cleanup for Produce:

1. Standard QuEChERS extraction followed by cleanup with Oasis PRiME HLB Plus cartridges.

Instrumentation Used

• Xevo TQ-GC GC-EI-MS/MS system for analyte detection and quantitation.
• Oasis PRiME HLB Plus solid-phase extraction cartridges.
• QuEChERS extraction kits and related consumables.

Main Results and Discussion

Edible Oils:

• Replacing hexane defatting and GPC cleanup with freeze-out and SPE reduced solvent use and preparation time.
• Organohalogen pesticides showed improved recoveries (<60% to >70%) when using freeze-out.
• SPE pass-through cleanup produced recoveries above 70% for all analytes, indicating negligible retention.
• Procedural standard calibration yielded high trueness (99.2–108.5%) and excellent linearity (R2>0.995).

Produce (Cucumber, Grape, Rice):

• QuEChERS extraction combined with SPE pass-through provided recoveries of 70–120% for over 95% of 208 target analytes.
• Repeatability was consistently below 20% RSD across all commodities at LOQ levels.

Benefits and Practical Applications

• Significantly reduced solvent consumption and preparation time compared to traditional methods.
• Enhanced recoveries and reliable quantitation for a broad spectrum of pesticides.
• Simplified workflow suitable for routine high-throughput residue testing in food safety laboratories.

Future Trends and Opportunities

• Further automation of SPE pass-through and freeze-out procedures to increase laboratory efficiency.
• Development of tailored sorbent materials for targeted class-specific cleanup.
• Extension of these simplified protocols to other challenging matrices and emerging contaminants.

Conclusion

The simplified cleanup approach using freeze-out defatting and Oasis PRiME HLB Plus pass-through SPE provides a solvent-efficient, rapid, and reliable solution for multi-residue pesticide analysis in complex food matrices. The methods demonstrate robust performance and are well-suited for routine monitoring.

References

• European Union (2019) Document No. SANTE 12682/2019: Guidance on Analytical Quality Control and Method Validation Procedures for Pesticide Residues Analysis in Food and Feed.