BRINGING RELIABLE DETERMINATION OF ANIONIC POLAR PESTICIDES IN FOOD TO THE ROUTINE LABORATORY

Significance of the Topic

Assessment of anionic polar pesticides such as glyphosate and ethephon is crucial due to growing regulatory scrutiny and food safety concerns. Standard reversed phase methods fail to retain these small polar analytes leading to demand for robust surveillance in food commodities.

Objectives and Study Overview

The study aimed to establish a single routine method for direct analysis of a broad range of polar anionic pesticides without derivatization or ion pairing. The approach focuses on extending beyond traditional targets glyphosate and AMPA to include additional acids and metabolites.

Methodology and Instrumentation

Extraction used the QuPPe protocol yielding acidified methanol extracts. Two UPLC-MS/MS methods were compared using an anionic polar pesticide column on an ACQUITY IClass with a Xevo TQ S micro detector:

• Method A employed buffered formic acid to enable inclusion of chlorate and perchlorate among at least thirteen analytes
• Method B used a formic acid mobile phase to enhance sensitivity for low ppb detection

Robust recovery and repeatability were confirmed in tomato, cucumber and wheat flour matrices.

Main Results and Discussion

• Retention criteria met with early eluting analytes exceeding two times the void volume ensuring good chromatographic behavior
• Baseline separation achieved for critical isobaric pairs such as AMPA and n acetyl AMPA as well as phosphonic acid and fosetyl aluminum
• RADAR full scan monitoring demonstrated potential matrix suppression in crude extracts and supported method development for cleaner extracts
• Trueness fell within 70 to 120 percent and precision below eight percent relative standard deviation at spiking levels from one to five times the target concentration

Benefits and Practical Applications

The workflow enables routine high throughput monitoring of diverse polar anionic pesticides in food with sensitivity beyond current maximum residue limits. Simplified sample preparation and unified chromatographic conditions reduce laboratory complexity and cost.

Future Trends and Potential Applications

Continued integration of full scan data acquisitions can support retrospective screening for emerging polar residues. Further column chemistry innovations may expand the analyte scope and resolve complex matrices without additional cleanup steps. Integration with high resolution platforms could improve selectivity and confirmatory capabilities.

Conclusion

A reliable single method for anionic polar pesticide determination has been validated for routine use on standard UPLC MS MS systems. It addresses retention, separation, matrix effects and detection challenges to deliver efficient and confident residue analysis in food.

Reference

• European Union Document No SANTE 11813 2017 Guidance Document on Analytical Quality Control and Method Validation Procedures for Pesticides Residues in Food and Feed
• European Commission QuPPe Method 2019 Eurl Pesticides
• Chamkasem N and Harmon T Anal Bioanal Chem 2016 408 18 4995 5004