Ultra-Fast Multiresidues Accurate Mass Screening Strategy

Significance of the Topic

In large-scale food production and international trade, ensuring the safety of raw materials through rapid and reliable pesticide residue screening is critical. High-resolution accurate mass spectrometry (HRAM) combined with ultra-fast chromatography addresses the need for high throughput analysis of tens of thousands of samples annually, enhancing food safety assessment and regulatory compliance.

Study Objectives and Overview

This study demonstrates a two-tier ultra-fast screening workflow for over 150 pesticide residues in complex fruit and vegetable matrices. The objectives are to achieve sub-ppb sensitivity, maintain high mass accuracy and precision, and integrate an intelligent reflex strategy that automatically triggers a secondary acquisition with fragmentation information upon initial detection.

Methodology and Instrumentation

Samples of broccoli, celery, and strawberry extracts were prepared using the QuEChERS EN protocol followed by dispersive solid phase extraction tailored to each matrix. Matrix-matched calibration curves (1 to 100 μg/L) were generated.

Instrumentation

• Liquid chromatography: Agilent 1290 Infinity II with a rapid gradient (4 min run time).
• Mass spectrometry: Revident LC/Q-TOF in positive electrospray ionization.
• Acquisition modes: First tier MS only at 3 Hz; second tier All Ions at 6 Hz with collision energies of 20 V and 40 V.
• Mass range: m/z 50–1,000; reference masses m/z 121.0509 and 922.0098 for mass accuracy correction.

Main Results and Discussion

The first-tier fast LC-MS method achieved mass accuracy within ±2 ppm for all 150+ pesticides and linearity (R² ≥ 0.99) across 1–100 ppb. Relative standard deviations were below 20% at 5, 10, and 15 ppb levels. Upon initial MS detection, the intelligent reflex workflow automatically reinjects flagged samples using the extended gradient and All Ions acquisition, yielding fragment ion spectra for confident compound identification. Data processing with MassHunter Quantitative Analysis and LC Screener allowed rapid screening, automated library matching, and isotopic fidelity assessment.

Benefits and Practical Applications

• High throughput: 4 min per injection for comprehensive multi-residue screening.
• Robust performance: low detection limits, excellent precision, and accuracy in complex matrices.
• Automated workflow: seamless transition from initial screen to detailed fragmentation analysis.
• Flexible library management: custom and third-party spectral libraries supported by ChemVista software.

Future Trends and Applications

Continued developments may include integration with artificial intelligence for pattern recognition, expansion of spectral libraries to cover emerging contaminants, miniaturization of HRAM platforms for field testing, and harmonization of multi-residue methods to meet evolving regulatory requirements.

Conclusion

The presented ultra-fast HRAM screening strategy combines a rapid LC gradient, accurate mass detection, and an intelligent reflex reinjection protocol to deliver reliable, high-throughput pesticide residue analysis. This workflow enables laboratories to efficiently manage large sample loads while maintaining rigorous analytical performance.

References

1. Simmermaker C. et al. Intelligent Reflex Targeted Reinjection Workflow for Pesticide Screening in Food Matrices; Agilent Technologies Application Note 5994-7312EN, 2024.