Development and applications of a pesticide multiresidue analysis turn-key system utilizing UHPLC-Orbitrap mass spectrometry and post data processing

Importance of the topic

Reliable multi-residue pesticide screening underpins food safety, environmental monitoring, and regulatory compliance. Traditional tandem mass spectrometry methods require extensive method development and may miss non-target compounds. High-resolution full-scan Orbitrap technology combined with automated data processing offers a comprehensive, sensitive, and efficient alternative.

Objectives and Study Overview

The primary aim was to assess a turn-key UHPLC–Orbitrap mass spectrometry system, coupled with dedicated software, for automated qualitative and quantitative analysis of 281 pesticide residues in various matrices. The study evaluated sensitivity, signal-to-noise performance, and detection capabilities in environmental and food samples at sub-ppb levels.

Methodology and Instrumentation

Sample preparation employed a modified QuEChERS protocol for fruit (orange, raisin) and solvent standards. Chromatographic separation used two UHPLC platforms (Accela and UltiMate 3000) equipped with Hypersil aQ C18 columns. Mass analysis was performed on Thermo Fisher Exactive and Exactive Plus Orbitrap detectors at four resolution settings (17 500 to 140 000 RPFWHM). Data acquisition ran full-scan mode with optimized source parameters. Post-acquisition processing leveraged Thermo Scientific Xcalibur for visualization and ExactFinder for targeted compound identification and quantification.

Results and Discussion

Increasing mass resolving power led to narrower extraction windows and significantly improved reconstructed ion chromatogram signal-to-noise ratios. Representative pesticides (diuron, dimethylvinphos, emamectin B1a) were quantifiable at loadings down to 0.78 pg with RSDs < 3 %. Across matrices, the number of detectable analytes rose with higher resolution and concentration, despite matrix suppression in orange and raisin. Of 281 targets, 265–270 compounds were identified at 0.5–1 ppb in solvent, with slightly reduced counts in complex matrices.

Benefits and Practical Applications

The described system enables rapid, high-throughput multi-residue screening without manual MRM optimization. Full-scan data allow retrospective analysis of unknowns and emerging contaminants. Automated workflows shorten analysis time, reduce false positives, and enhance quantitative consistency down to fg-level on-column loadings.

Future Trends and Potential Applications

• Expand target databases to include pharmaceuticals, hormones, antibiotics, and water-treatment by-products.
• Improve cheminformatic algorithms for non-target and unknown compound discovery.
• Integrate cloud-based libraries and AI-driven identification to accelerate regulatory compliance and environmental forensics.

Conclusion

The UHPLC–Orbitrap turn-key system with ExactFinder software delivers robust, sensitive, and automated pesticide multi-residue analysis across diverse matrices. High resolution enhances detectability and quantification precision, offering a powerful tool for routine QA/QC and research laboratories.

Instrumentation Used

• QuEChERS sample preparation kits
• Thermo Scientific Accela High Speed LC and UltiMate 3000 RSLC systems
• Thermo Hypersil aQ C18 columns (2.1×100 mm, 1.9–3 µm)
• Exactive and Exactive Plus Orbitrap MS
• Thermo Scientific Xcalibur and ExactFinder software
• Microsoft Excel for data compilation

References

1. Zhang K.; Wong J. W.; Yang P.; Tech K.; DiBenedetto A. L.; Lee N. S.; Hayward D. G.; Makovi C. M.; Krynitsky A. J.; Banerjee K.; Jao L.; Dasgupta S.; Smoker M. S.; Simonds R.; Schreiber A. J. Agric. Food Chem. 2011, 59(14), 7636–7646.