Comparison of Sample Preparation Methods for Pesticide Analysis in Botanical Dietary Supplement Materials

Importance of the Topic

The presence of pesticide residues in botanical dietary supplements (BDS) poses a significant safety and quality concern due to contamination risks during cultivation, processing, and storage. Reliable, high-throughput analytical methods capable of detecting hundreds of residues in diverse plant matrices are essential for regulatory compliance and consumer protection.

Objectives and Study Overview

This application note compares a novel, unified sample preparation workflow against traditional dual-method approaches for multiclass pesticide screening in BDS materials. Over 440 pesticides were targeted by liquid chromatography-tandem mass spectrometry (LC/MS/MS) and gas chromatography-tandem mass spectrometry (GC/MS/MS). The study evaluates recovery, reproducibility, matrix effects, and overall efficiency.

Methodology and Instrumentation

• Extraction: QuEChERS salt-out extraction (AOAC buffered) of 0.5–1 g homogenized sample using acetonitrile and water.
• Cleanup (new method): Agilent Captiva EMR mixed-mode passthrough cartridges (GPD, LPD, GPF combinations) to remove pigments, lipids, and co-extractives without preconditioning.
• Cleanup (traditional methods): Dispersive solid-phase extraction for LC/MS/MS; PSA/graphitized carbon black SPE for GC/MS/MS, requiring toluene/acetone washes and concentration steps.
• Instrumentation: Triple quadrupole LC/MS/MS and GC/MS/MS systems configured for >220 LC-amenable and >227 GC-amenable pesticides.

Key Results and Discussion

The unified EMR-based workflow delivered 70–120% recoveries with <20% RSD for over 82% of 447 pesticides across complex BDS matrices (green tea, black tea, curcumin, barberry root, peppermint). Matrix interference was reduced, eliminating false positives (e.g., azinphos-ethyl in saffron). A proficiency test against a reference spice sample confirmed comparable detection accuracy to traditional methods (<15% difference).

Benefits and Practical Applications

• Single-method prep for both LC/MS/MS and GC/MS/MS streamlines lab logistics, reduces consumables (50% solvent savings), and halves analyst time.
• High sample recovery (>90%) supports varied post-extraction treatments.
• Enhanced throughput and reproducibility improve data alignment across platforms.

Future Trends and Potential Applications

Continued integration of mixed-mode sorbents and automation will further accelerate high-throughput pesticide screening. Expanding multiresidue panels and adapting to emerging botanical matrices will meet evolving regulatory demands and quality-control challenges.

Conclusion

The EMR mixed-mode passthrough cleanup represents an efficient, greener alternative to traditional dual-prep workflows, delivering robust multiclass pesticide analysis in botanical supplements with high throughput and consistent data quality.

References

• Hayward D.G. et al., Anal. Chem. 2013, 85, 4686–4693.
• Zou A. et al., Agilent Technologies Application Note, 2022.
• SANTE/11312/2021: EU Guidance on Pesticide Residue Analysis.