Simultaneous Screening and Quantification of Pesticide Residues in Red Cabbage

Significance of the Topic

Simultaneous multi-residue screening and quantification of pesticides in food matrices are critical for ensuring consumer safety and regulatory compliance. High-resolution mass spectrometry coupled with UHPLC enables rapid, accurate detection of a wide range of compounds at low levels. Improved throughput and sensitivity reduce analysis time and support monitoring of complex food samples such as leafy vegetables.

Objectives and Study Overview

This work presents a validated All Ions MS/MS workflow using an Agilent 6545 LC/Q-TOF system to screen and quantify 415 pesticide residues in red cabbage. The method follows China GB 20769-2008 for extraction and applies Agilent All Ions MS/MS acquisition for simultaneous collection of precursor and fragment ions. Performance was benchmarked through matrix-matched calibration, recovery tests, and participation in the 2019 EU pesticide screening proficiency test.

Methodology

The sample preparation and cleanup were based on a conventional SPE approach:

• Weigh and homogenize 10 g cabbage with 1% acetic acid in acetonitrile
• Salt-assisted phase separation using NaCl and MgSO₄
• Evaporation and concentration of the organic phase
• Carbon/NH₂ SPE purification and final reconstitution in acetonitrile/water

Instrumentation Used

Separation was performed on an Agilent 1290 Infinity II UHPLC with a ZORBAX SB-C18 column (100 × 2.1 mm, 3.5 µm) using a gradient of 0.1% formic acid/5 mM ammonium acetate and acetonitrile at 0.4 mL/min. Detection employed an Agilent 6545 LC/Q-TOF MS with Dual Jet Stream ESI under All Ions MS/MS mode (collision energies 0, 15, 35 V; acquisition rate 4 spectra/s; full scan m/z 50–1 000).

Results and Discussion

Screening detection limits for most pesticides were ≤5 µg/kg and quantification limits ≤10 µg/kg. Linearity was excellent (R² > 0.99) over 5–100 µg/kg for 368 compounds. Recoveries at LOQ, 2× LOQ, and 10× LOQ ranged 70–120% (RSD < 20%) for 413 of 415 pesticides. Collision energy optimization showed that sequential energies of 0/15/35 V maximized identification of 209 test compounds. An acquisition rate of 4 spectra/s balanced data density and sensitivity. Participation in the EUPT proficiency test yielded 100% correct identification of 16 unknown incurred pesticides and quantification of 20 spiked analytes with Z-scores within ±1.1.

Benefits and Practical Applications

This All Ions MS/MS approach achieves high-throughput analysis of hundreds of pesticides in a single run, reducing the need for compound-specific MS/MS methods and extensive reference standards. The method supports fast screening in routine QA/QC labs and proficiency testing with reliable sensitivity and accuracy.

Future Trends and Potential Applications

Adapting this workflow to other fruits and vegetables can broaden monitoring scope. Integration with advanced data-processing algorithms and expanded spectral libraries will further streamline identification. Emerging HRMS platforms and machine learning–driven spectral deconvolution may enhance multi-residue screening capabilities.

Conclusion

The developed UHPLC-Q-TOF All Ions MS/MS method provides robust, sensitive, and high-throughput screening and quantification of 415 pesticides in red cabbage. It meets regulatory criteria, performs well in proficiency tests, and can be extended to diverse plant matrices.

References

1. Wang Z. et al. Anal. Methods 2015, 7(15), 6385.
2. Gómez-Ramos M. M. et al. J. Chromatogr. A 2013, 1287, 24.
3. SANTE/12682/2019 guidelines.
4. Agilent Technologies Application Note 5994-0322EN, 2018.
5. Naz S. et al. Anal. Chem. 2017, 89, 7933.
6. Xie Y. et al. Chin. J. Chromatogr. 2021, 39, 301.
7. GB 20769-2008.
8. Xie Y. et al. Chin. J. Food Safety & Quality 2020, 11, 6437.