Using HRAM LC/QTOF for Target and Suspect Screening in Multi-Residue Pesticide Analysis

Significance of the topic

High resolution accurate mass LC/QTOF analysis is transforming multi-residue pesticide screening by offering simultaneous targeted quantitation and retrospective suspect screening. Compliance with stringent EU SANTE/12682/2019 guidelines demands precise mass measurements and robust ion ratio confirmation. Integrating both targeted and untargeted workflows enhances laboratory efficiency and broadens detection capabilities for routine monitoring of food and feed.

Objectives and overview of the study

This study demonstrates the transfer of a validated triple quadrupole LC-MS/MS method to a high resolution QTOF platform for over 200 pesticide analytes. The goals were to validate mass accuracy, precision, and retention time reproducibility for targeted quantitation, and to implement suspect screening workflows that leverage comprehensive DIA-MS/MS data for retrospective analysis.

Methodology

Sample preparation followed established QuEChERS protocols for apple, tomato, and orange matrices. Extracts in acetonitrile were directly injected with a water co-injection step to sharpen early peaks.

Chromatographic separation employed a Restek Raptor Biphenyl column with a binary gradient of 0.004% formic acid in ammonium formate aqueous solution and methanol.

The LCMS-9030 QTOF system with electrospray ionization in positive mode acquired a TOF survey scan (140–900 m/z) and 31 DIA-MS/MS events covering 65–900 m/z. A 0.875 second cycle time yielded 10–20 data points per peak. External mass calibration was performed every few days.

Used Instrumentation

• Shimadzu LCMS-9030 high resolution QTOF with ESI source
• Restek Raptor Biphenyl column, 100 × 2.1 mm, 2.7 μm
• LabSolutions Insight software for targeted and suspect screening workflows

Main results and discussion

Targeted quantitation achieved detection of all 200+ pesticides at the default MRL of 0.010 mg/kg with mass accuracy within ±5 ppm and retention time variation within ±0.1 minute. Repeatability (RSDr) was below 20% for low-level calibration standards (0.002–0.1 mg/kg) across six replicates, yielding 183 compounds under 20% at 0.002 mg/kg. Robustness testing at MRL level (n=50 injections) showed 194 compounds with area RSD under 10% and 203 under 20%.

Suspect screening employed component detection algorithms to isolate chromatographic features and match them against a suspect list of compound formulas, target masses, and retention windows. Retrospective analysis confirmed that suspect screening results aligned with targeted workflows as demonstrated in the processed chromatograms. Figure 1 illustrates mass accuracy and retention time evaluation in LabSolutions Insight and Figure 2 outlines the suspect screening algorithm steps including feature detection and list matching.

Benefits and practical applications

• Unified acquisition for targeted quantitation and untargeted suspect screening reduces analysis time
• Regulatory compliance with mass accuracy, ion ratio, and precision requirements
• Retrospective data mining enables discovery of emerging or unexpected residues without additional runs
• High throughput support for routine monitoring in QA/QC and research laboratories

Future trends and opportunities

Advancements in data processing algorithms and machine learning will further improve suspect and non-target screening sensitivity. Integration with high-throughput sample prep automation will increase lab productivity. Expanding workflows to cover new matrices, metabolites, and degradation products will support comprehensive food safety assessments. Cloud-based sharing of spectral libraries and collaborative platforms will enhance method development and regulatory harmonization.

Conclusion

The HRAM LC/QTOF DIA-MS/MS approach delivers a robust, high-speed solution for multi-residue pesticide analysis that meets EU SANTE/12682/2019 validation criteria. Combining targeted quantitation with retrospective suspect screening in a single acquisition streamlines workflows and expands detection capabilities in food and feed testing.

References

• EU SANTE/12682/2019 Analytical Quality Control and Method Validation Procedures for Pesticides Residues Analysis in Food and Feed