Enhanced Food Safety Testing - A pesticide screening methodology using the Agilent 6546 LC/Q-TOF and MassHunter Quantitative Analysis Software 10.0 LC/Q-TOF Screener Tool

Significance of the topic

The rapid expansion of pesticide monitoring requirements in food safety testing has driven demand for high-throughput, comprehensive workflows that balance quantitative analysis with broad suspect screening. Traditional triple quadrupole methods require extensive calibration and are limited by target lists, creating cost and time burdens as regulatory lists grow. Combining accurate-mass quadrupole time-of-flight (Q-TOF) screening with software-driven suspect workflows addresses these challenges, enabling simultaneous quantitation of priority analytes and discovery of additional residues in complex matrices.

Objectives and overview of the study

This application note presents a unified workflow leveraging the Agilent 6546 LC/Q-TOF system and MassHunter Quantitative Analysis software 10.0 Screener tool to:

• Screen and quantitate nearly 200 priority pesticides across diverse food matrices in a single injection.
• Perform suspect screening for an additional 180+ compounds without predefined standards.
• Demonstrate method performance in four representative foods and real-world samples.

Methodology and instrumentation used

Four food matrices (black tea, broccoli, avocado, strawberry) were prepared by the QuEChERS EN15662 protocol with matrix-matched cleanup. A comprehensive pesticide mix was diluted to generate five calibration levels (5–100 ppb). Priority targets (195 compounds) underwent full calibration; suspects (182 compounds) were screened based on retention time estimates and spectral matching.

Instrumental conditions:

• Agilent 1290 Infinity II Prime LC with ZORBAX Eclipse Plus C18 column (3 × 150 mm, 1.8 µm).
• Agilent 6546 LC/Q-TOF MS with All Ions MS/MS acquisition (0, 20, 40 eV collision energies).
• Reference masses: purine (m/z 121.0509) and HP-921 (m/z 922.0098).
• Mobile phases: water and methanol both containing ammonium formate, ammonium fluoride, and formic acid; gradient from 2% to 100% B over 16 min.
• Data processing via SureMass conversion and MassHunter Quantitative Analysis 10.0 Screener for automated flagging.

Main results and discussion

At the 5 ppb quantitation level, all 195 priority targets produced signal-to-noise >3, RSDs <20%, and linearity (R2 > 0.99) in three injections for strawberry, avocado, and broccoli; 145 targets met these criteria in black tea after dilution. The Screener workflow colored compounds green (pass), orange (review), or red (not detected) to streamline data review. Suspect screening effectively detected additional residues without calibration curves. Mass accuracy remained within ±2 ppm across the gradient at both 10 and 100 ppb.

In fortified samples (10 and 100 ppb), nearly all priority and suspect compounds were identified. Analysis of 16 unknown strawberry samples from organic and conventional sources revealed 3–12 pesticides per sample, with conventional batches showing more residues. Both target quantitation and suspect discovery were achieved in one injection, reducing analysis complexity.

Contributions and practical applications of the method

The integrated LC/Q-TOF Screener approach:

• Reduces standard costs by minimizing calibration requirements for suspects.
• Combines quantitative data and suspect screening in a single workflow, cutting data-review time.
• Delivers high confidence through accurate mass, isotopic fidelity, and co-elution scoring.
• Adapts to evolving regulatory needs by expanding or refining target and suspect lists without re-acquisition.

Future trends and opportunities for application

Emerging directions include:

• Expansion of high-resolution accurate-mass libraries for more comprehensive suspect screening.
• Automated method optimization using machine-learning algorithms to refine qualifier selection and co-elution metrics.
• Integration with laboratory information management systems (LIMS) for real-time compliance reporting.
• Miniaturized or multiplexed sample preparation to further boost throughput.
• Application to non-crop commodities and environmental matrices for broader residue surveillance.

Conclusion

This study demonstrates that the Agilent 6546 LC/Q-TOF coupled with MassHunter Quantitative Analysis 10.0 Screener offers a robust, streamlined solution for simultaneous pesticide quantitation and suspect screening. By delivering excellent reproducibility, mass accuracy, and linearity across challenging food matrices, the method meets regulatory requirements while reducing analytical burden. Its flexibility and high confidence make it well suited for modern food safety laboratories facing expanding compound scopes.

Instrumentation

• Agilent 1290 Infinity II Prime LC
• Agilent 6546 LC/Q-TOF MS
• Agilent MassHunter Quantitative Analysis software 10.0 with Screener tool

Reference

1. European Commission SANTE/11813/2017. Guidance Document on Analytical Quality Control and Method Validation for Pesticide Residues Analysis in Food and Feed. November 2017.
2. Miladi, M. et al. High-Throughput Pesticide Residue Analysis Using an Agilent Ultivo Triple Quadrupole LC/MS and the MassHunter Productivity App, Agilent Technologies Application Note 5994-0196EN, 2018.