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

Significance of the Topic

The safety of botanical dietary supplements depends critically on reliable multiresidue analysis of pesticide contaminants. Complex, dry plant matrices can carry hundreds of pesticide residues introduced during cultivation and processing. A unified, efficient sample preparation is essential to ensure consumer safety, regulatory compliance, and laboratory productivity.

Aims and Overview of the Study

This application note evaluates a streamlined single‐workflow sample preparation for both liquid chromatography–tandem mass spectrometry (LC/MS/MS) and gas chromatography–tandem mass spectrometry (GC/MS/MS) analysis of over 440 pesticides in botanical dietary supplement (BDS) materials. Various BDS matrices (green tea, black tea, herbal tea, peppermint tea, barberry root, curcumin complex) were compared against traditional separate QuEChERS plus dispersive SPE (dSPE) or solid-phase extraction (SPE) procedures.

Methodology and Instrumentation

The developed protocol uses 0.5 g of homogenized sample with an AOAC‐buffered QuEChERS extraction, followed by mixed‐mode passthrough cleanup using Agilent Captiva EMR cartridges (EMR-GPD, EMR-LPD, EMR-GPF) selected according to matrix pigmentation. After loading the acidified extract onto the cartridge, eluates are split for GC/MS/MS (1 mL) and LC/MS/MS (0.5 mL) post-treatment as per standard methods. Triple quadrupole LC/MS and GC/MS instruments were employed for detection.

Main Results and Discussion

The EMR cleanup achieved > 90% extract recovery volume and removed organic acids, pigments, lipids, and sugars, greatly reducing matrix interferences (e.g., azinphos-ethyl in saffron). Recovery studies at 50 ng/g spiking delivered 70–120% recovery and RSDs < 20% for > 82% of 447 pesticides in complex BDS matrices. Compared to traditional workflows, the single EMR method cut solvent use (10 mL vs. 48 mL), halved sample prep time (5–6 h vs. 12 h), and eliminated the need for toxic toluene. Proficiency testing confirmed equivalent quantitative accuracy (< 15% difference) across critical analytes.

Benefits and Practical Applications of the Method

• Unified workflow for LC/MS/MS and GC/MS/MS reduces bench time, consumables, and labor.
• High sample recovery volume supports multiple post-treatments and improves throughput.
• Mixed-mode EMR cleanup enhances traceability by aligning data sets from both detection platforms.
• Elimination of toxic solvents increases operator safety and reduces environmental impact.

Future Trends and Applications

Emerging directions include integration of EMR cleanup with automated liquid handlers, expansion of mixed-mode cleanup to other complex food and botanical matrices, adoption of greener solvent systems, and coupling with high-resolution mass spectrometry. Standardizing unified prep protocols can further streamline regulatory workflows and support large-scale monitoring programs.

Conclusion

The Agilent Captiva EMR mixed-mode passthrough cleanup integrated with QuEChERS extraction provides a rapid, cost-effective, and environmentally friendly sample preparation for comprehensive multiresidue pesticide analysis in BDS materials. This single method achieves regulatory‐grade performance for LC/MS/MS and GC/MS/MS detection, enhances laboratory efficiency, and reduces resource consumption.

References

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