Sub 1 μg/kg Detection of Glyphosate and Other Anionic Polar Pesticides Using a Generic Extraction and Detection by LC-MS/MS

Importance of the Topic

The routine detection of anionic polar pesticides such as glyphosate and its metabolites is essential for ensuring food safety and meeting regulatory requirements. Traditional single-residue methods are time‐consuming; a generic extraction combined with high‐sensitivity LC-MS/MS enables multi-residue analysis with lower limits of quantification and improved laboratory efficiency.

Objectives and Study Overview

This study evaluates a generic QuPPe version 12 extraction protocol paired with the Xevo TQ Absolute MS system to achieve sub-µg/kg detection of ten anionic polar pesticides in representative “wet” (cucumber) and “dry” (wheat flour) matrices.

Methodology

• Sample Preparation: Blank matrix extracts were generated following QuPPe v12. Cucumber standards covered 0.5–200 µg/kg (0.25–100 ng/mL in vial), wheat flour standards 2–200 µg/kg (0.25–25 ng/mL in vial).
• Chromatographic Conditions: Separation on an Anionic Polar Pesticide Column (5 µm, 2.1 × 100 mm) at 50 °C, mobile phases 0.9% formic acid in water (A) and acetonitrile (B), 10 µL injection volume.

Instrumentation

• LC System: ACQUITY UPLC I-Class PLUS (FL-SM).
• MS System: Xevo TQ Absolute, electrospray ionization in negative mode, MRM acquisition.
• Key Parameters: Transitions and collision energies as optimized for each analyte (see Table 1 summary).

Main Results and Discussion

The method achieved limits of quantification down to 0.5 µg/kg in cucumber and 2 µg/kg in wheat flour for most compounds (AMPA at 5 µg/kg). Calibration curves showed correlation coefficients ≥ 0.99 and residuals <20%. Accuracy (trueness) ranged from 89% to 117%, with repeatability (RSD) below 9%. Chromatograms at 1 µg/kg in cucumber demonstrated clear separation and sensitivity enhancements from the Xevo TQ Absolute system. The QuPPe extraction performed robustly across wet and dry commodities, with minimal matrix effects when optimized dilution factors were applied.

Benefits and Practical Applications

• Multi-residue capability reduces analysis time and solvent usage compared to single-analyte methods.
• Sub-µg/kg sensitivity supports compliance with stringent regulatory thresholds.
• High method robustness through lower injection volumes and reduced matrix load enhances instrument uptime and maintenance intervals.

Future Trends and Opportunities

Further development may include broader analyte panels, automation of QuPPe workflows, coupling with high-resolution MS for non-targeted screening, and miniaturized extraction techniques to reduce solvent consumption and sample requirements.

Conclusion

The combination of QuPPe v12 generic extraction with the Xevo TQ Absolute MS system delivers a streamlined, sensitive, and robust approach for quantifying glyphosate and other anionic polar pesticides at sub-µg/kg levels in diverse food matrices, meeting current and future regulatory demands.

Reference

1. M. Anastassiades et al. Quick Method for the Analysis of Highly Polar Pesticides in Food (QuPPe-PO-Method) Version 12, EURL-SRM, 2021.
2. S. Hird, S. Adams, J. De-Alwis. Evaluation of Highly Polar Anionic Pesticides in Foodstuffs Using LC-MS/MS, Waters Application Note 720007505, 2022.
3. J. De-Alwis et al. Interlaboratory Study of Anionic Polar Pesticides in Crops and Foodstuffs, Waters Application Note 720007154, 2021.
4. K. Kumar et al. Determination of Anionic Polar Pesticides in Grapes Using UPLC-MS, Waters Application Note 720006925, 2020.
5. E. Ross et al. Determination of Anionic Polar Pesticides in High Water Foodstuffs, Waters Application Note 720006645, 2019.