Analysis of Pesticides in Kale Using the Agilent 7010C Triple Quadrupole GC/MS with Agilent Bond Elut QuEChERS High Pigment dSPE with Carbon S Cleanup

Importance of the Topic

This application note addresses the critical need for accurate quantitation of pesticide residues in leafy green vegetables, using kale as a challenging high-pigment matrix. Ensuring food safety and compliance with regulatory limits for over 100 pesticides supports public health and trade requirements.

Objectives and Study Overview

The primary objective was to demonstrate a streamlined workflow for sensitive, high-throughput analysis of more than 100 GC-amenable pesticides in kale. The study evaluated:

• The QuEChERS EN 15662 extraction coupled with Agilent Bond Elut QuEChERS High Pigment dSPE using Carbon S sorbent.
• The performance of an Agilent 8890 GC with a 7010C triple quadrupole GC/MS in dynamic MRM mode.

Methodology and Instrumentation

Sample Preparation:

• QuEChERS EN 15662 extraction in acetonitrile.
• dSPE cleanup using Agilent Bond Elut QuEChERS High Pigment kit (EN-like) with Carbon S sorbent to remove pigments while preserving analyte recovery.

Instrumentation:

• Agilent 8890 GC system with a 7693A autosampler, multimode inlet operated in splitless reversed three-layer switching, and backflush via Ultimate Union.
• Agilent 7010C triple quadrupole GC/MS configured for dynamic MRM (dMRM) acquisition.
• Dual Agilent J&W HP-5ms Ultra Inert columns (15 m × 0.25 mm, 0.25 µm) in parallel.
• Helium carrier gas, HES source, N₂ collision gas, MassHunter Workstation software.

Main Results and Discussion

Calibration and Linearity:

• Matrix-matched calibration from 0.5 to 50 ppb (w/v), with R² > 0.990 for all targets.

Recovery and Precision:

• 98.6% of pesticides exhibited recoveries between 70–130% at 24 ppb in kale.
• Repeatability (n = 6) showed RSDs < 25% for 99.3% of compounds.

Chromatography and Sensitivity:

• MRM chromatogram of 150 analytes achieved clear separation and low background.
• Dynamic MRM enabled high sensitivity and selectivity in a 20 min run time.

Benefits and Practical Applications

This method offers:

• Rapid sample throughput suitable for routine food safety laboratories.
• Robust performance across a broad pesticide panel in pigmented matrices.
• Compliance with international regulatory standards.

Future Trends and Opportunities

Potential developments include:

• Extension to other complex matrices (fruits, cereals, processed foods).
• Integration with high-resolution or hybrid mass spectrometry for non-target screening.
• Automation of sample preparation and data processing to further increase throughput.
• Miniaturized or portable GC/MS platforms for on-site rapid testing.

Conclusion

The combination of QuEChERS EN 15662 extraction, Carbon S dSPE cleanup, and Agilent 7010C triple quadrupole GC/MS in dMRM mode provides a reliable, high-throughput solution for quantifying over 100 pesticides in kale. The method delivers excellent linearity, accuracy, and precision while effectively removing matrix interferences.

References

1. González-Curbelo MÁ, et al. Evolution and Applications of the QuEChERS Method. Trends Anal Chem. 2015;71:169–185.
2. Varela-Martínez DA, et al. Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) Extraction. In: Liquid-Phase Extraction. Elsevier; 2020:399–437.
3. Ferlin C, Zhao L. Analysis of Pesticide Residues in Spinach Using AOAC Pigmented dSPE with Carbon S Cleanup and LC/MS/MS. Agilent Technologies App Note 5994-4769EN. 2022.
4. Yang X, Li Z. Quantitative Analysis of Pesticides in Celery and Grape, Agilent App Note 5994-4763EN. 2022.
5. Westland J. Analysis of Pesticides in Tomato and Kale on GC/MS/MS with Agilent Bond Elut QuEChERS EN High Pigment dSPE with Carbon S. Agilent App Note 5994-5050EN. 2022.
6. Andrianova A, Zhao L. Five Keys to Unlock Maximum Performance in the Analysis of Over 200 Pesticides in Challenging Food Matrices by GC/MS/MS. Agilent App Note 5994-4965EN. 2022.