Multi-Residue Pesticide Analysis in Herbal Products Using Accelerated Solvent Extraction with a Triple Quadrupole GC-MS/MS System

Significance of the Topic

The analysis of pesticide residues in herbal products and teas is critical for consumer safety and regulatory compliance. Complex matrices, worldwide sourcing, and diverse pesticide chemistries require sensitive, high-throughput multi-residue methods.

Objectives and Study Overview

This study demonstrates a routine screening method for more than 200 pesticides in various herbal matrices (teas, dried herbs, seeds) using accelerated solvent extraction, gel permeation cleanup, and triple quadrupole GC-MS/MS. The goal is to meet EU MRL requirements (0.01 mg/kg) with minimal manual intervention.

Methodology and Instrumentation

Sample preparation employed ASE 350 (10 g sample, ethyl acetate/cyclohexane 1:1, 120 °C, 100 bar). Cleanup was performed by GPC on Bio-Beads S-X3 with the same solvent mix. Extracts were concentrated and introduced by TriPlus RSH autosampler via PTV splitless injection (1 µL). Chromatography used TRACE GC 1310 with a 40 m × 0.18 mm, 5%-phenyl column and temperature program from 70 °C to 290 °C. Detection on TSQ 8000 in timed-SRM mode optimized sensitivity and acquisition duty cycle.

Main Results and Discussion

Calibration over six points (0.004–1 µg/mL) yielded R² > 0.99. LODs in lemon peel matrix at 4 ppb exhibited S/N > 12 for key pesticides. Robust performance over ≥ 500 heavy-matrix injections required no frequent source cleaning. Precision studies (50 samples) reported CVs < 10% for most analytes. Real samples revealed several pesticides above MRLs (up to 0.479 mg/kg).

Benefits and Practical Applications

• Throughput: 30 min runs allow ~ 48 samples/day including QC.
• Scope: Simultaneous detection of > 200 pesticides in one GC-MS/MS method.
• Robustness: Timed-SRM and modular injector reduce downtime.
• Compliance: Meets SANCO and Codex Alimentarius standards.
• Automation: TraceFinder™ software integrates calibration, confirmation, flagging, and reporting.

Future Trends and Potential Applications

Integration with LC-MS/MS for polar and non-volatile residues, adoption of high-resolution MS for non-target screening, AI-driven data analysis, and miniaturized green extraction techniques will further enhance multi-residue workflows.

Conclusion

The ASE-GPC cleanup coupled with TSQ 8000 GC-MS/MS in timed-SRM mode provides a sensitive, robust, and automated solution for multi-residue pesticide analysis in complex herbal matrices, ensuring reliable results and regulatory compliance.

References

1. SANCO/12495/2011 Method Validation and Quality Control Procedures for Pesticide Residue Analysis in Food and Feed.
2. Codex Alimentarius Pesticide Maximum Residue Levels.
3. German LFGB L 00.00-34 Modul E9 Accelerated Solvent Extraction.
4. Thermo Fisher Scientific Pesticide Method Reference, 2nd Edition, 2011.