A Multiresidue Method for Pesticide Analysis Using an Orbitrap Tribrid Mass Spectrometer and Automatic Background Exclusion

Significance of the Topic

A robust multiresidue pesticide screening method is essential to meet regulatory maximum residue levels (MRLs) and ensure food safety. High-throughput techniques enable simultaneous quantification and screening of hundreds of pesticide residues with precision and reliability.

Objectives and Study Overview

This study aimed to develop a comprehensive workflow on the Thermo Scientific Orbitrap ID-X Tribrid mass spectrometer for:

• Quantitative determination of 250 pesticide residues in food matrices.
• Enhanced untargeted screening via automated background exclusion.

Methodology and Instrumentation

Sample Preparation:

• Strawberries were homogenized and extracted using a QuEChERS kit with acetonitrile.
• Matrix-matched calibration standards were prepared at 0.05–200 ppb.

Chromatography:

• Vanquish UHPLC with Accucore aQ C18 column (100 × 2.1 mm, 2.6 μm).
• Gradient elution using water/methanol mobile phases (5 mM ammonium formate, 0.1% formic acid).
• Flow rate of 300 µL/min, 15-minute total run time.

Mass Spectrometry:

• Orbitrap ID-X Tribrid MS employing AcquireX for background exclusion versus Data-Dependent Acquisition (DDA).
• Full MS at 60,000 resolution (AGC target 2 × 10^5); MS/MS at 15,000 (AGC 1 × 10^4), HCD stepped energies of 20/40/70%.

Data Processing:

• TraceFinder software for quantitation (5 ppm mass tolerance) and screening using the mzVault library.

Main Results and Discussion

Limits of Quantitation and Linearity:

• LOQs at or below 1 ppb for 82% of pesticides.
• Linear calibration curves across 0.05–200 ppb.

Precision and Accuracy:

• %RSD and %CV ≤ 10% at LOQs for 94% of analytes; most compounds showed ≤ 5% CV over the calibration range.

Background Exclusion Benefits:

• AcquireX workflow significantly increased the number of identified pesticides at low ppb levels compared to standard DDA.
• Automated exclusion lists improved library match rates and reduced matrix interference.

Benefits and Practical Applications

This workflow supports high-throughput compliance testing in food safety and QA/QC laboratories by combining sensitive, accurate quantitation with broad untargeted screening. Automated background exclusion enhances the detection of trace pesticide residues and streamlines data acquisition.

Future Trends and Potential Uses

Advancements such as real-time exclusion list updates, expanded spectral libraries, and AI-driven data analysis will further enhance method performance. Extension of the approach to diverse matrices (e.g., soils, water) and environmental monitoring is anticipated.

Conclusion

The Orbitrap ID-X Tribrid mass spectrometer with AcquireX delivers confident, reproducible multi-pesticide analysis at sub-ppb sensitivity in a single 15-minute run. Automated background exclusion substantially improves sensitivity and identification confidence, establishing a powerful tool for routine residue surveillance.

Instrumentation Used

• Thermo Scientific Vanquish UHPLC system
• Accucore aQ C18 column (100 × 2.1 mm, 2.6 μm)
• Orbitrap ID-X Tribrid mass spectrometer
• AcquireX automated background exclusion workflow
• Thermo TraceFinder software and mzVault spectral library
• QuEChERS extraction kit

References

Paul Dewsbury, Anastasia Kalli, Seema Sharma, Charles Yang, Dipankar Ghosh. Thermo Fisher Scientific. “A Multiresidue Method for Pesticide Analysis Using an Orbitrap Tribrid Mass Spectrometer and Automatic Background Exclusion.”