SUB 1μG/KG DETECTION OF GLYPHOSATE AND OTHER ANIONIC POLAR PESTICIDES USING A GENERIC EXTRACTION AND DETECTION BY LC-MS/MS

Significance of the topic

Routine analysis of anionic polar pesticides plays a vital role in ensuring food safety and regulatory compliance. The QuPPe method enables a generic extraction that covers multiple polar, anionic pesticides in diverse food matrices. By combining it with high-sensitivity LC-MS/MS, laboratories can streamline workflows, reduce sample prep time, and achieve sub-µg/kg detection limits.

Objectives and overview

This study evaluates the performance of a generic QuPPe extraction paired with LC-MS/MS using the Waters ACQUITY UPLC I-Class PLUS and Xevo TQ Absolute systems. The aim is to determine limits of quantification (LOQs), method accuracy, repeatability, and calibration quality for ten anionic polar pesticides in cucumber and wheat flour matrices.

Methodology and instrumentation

• Sample preparation: QuPPe version 12 protocol for wet (cucumber) and dry (wheat flour) commodities.
• Calibration standards: 0.5–200 µg/kg (cucumber) and 2–200 µg/kg (wheat flour).
• Chromatography: ACQUITY UPLC I-Class PLUS with Waters Anionic Polar Pesticide Column (2.1×100 mm, 5 µm; 50 °C).
• Mobile phases: A=0.9% formic acid in water; B=0.9% formic acid in acetonitrile; injection volume 10 µL.
• Mass spectrometry: Xevo TQ Absolute; electrospray ionization in negative mode; MRM acquisition.

Key results and discussion

• LOQs ranged from 0.5 µg/kg in cucumber to 2 µg/kg in wheat flour (AMPA at 5 µg/kg) with calibration residuals <20% and R² ≥0.99.
• Chromatograms at 1 µg/kg in cucumber show sharp, well-resolved peaks for all analytes.
• Method accuracy assessed at 1 and 10 µg/kg (cucumber) and 10 and 50 µg/kg (wheat flour) demonstrated recoveries within acceptable ranges and repeatability (n=10) under 15% RSD.
• Lower injection volumes can enhance robustness by reducing matrix load.

Benefits and practical applications

The combined QuPPe extraction and Xevo TQ Absolute analysis provides:

• Versatility across multiple polar, anionic pesticides and food matrices.
• Sub-µg/kg sensitivity without complex cleanup.
• Efficient workflow for routine QA/QC and regulatory monitoring.
• Improved system robustness through reduced matrix introduction.

Future trends and opportunities

• Integration of multi-residue workflows to cover wider classes of polar analytes.
• Further miniaturization and automation of sample preparation.
• Expansion to challenging matrices such as processed foods and environmental samples.
• Advancements in high-resolution MS to enhance screening capabilities.

Conclusion

The generic QuPPe extraction coupled with the high-sensitivity Xevo TQ Absolute LC-MS/MS system delivers reliable, efficient analysis of anionic polar pesticides at sub-µg/kg levels. This approach streamlines laboratory workflows, ensures compliance with regulatory requirements, and enhances robustness through minimal sample cleanup.

Used instrumentation

• ACQUITY UPLC I-Class PLUS with Waters Anionic Polar Pesticide Column.
• Xevo TQ Absolute triple quadrupole MS system.

References

1. Anastassiades M. et al. QuPPe version 12 protocol, EURL-SRM, 2021.
2. Hird S., Adams S., De-Alwis J. Waters Application Note 720007505, 2022.
3. De-Alwis J. et al. Waters Application Note 720007154, 2021.
4. Kumar K.P. et al. Waters Application Note 720006925, 2020.
5. Ross E. et al. Waters Application Note 720006645, 2019.