Identification and Quantitation of Pesticides in Chamomile and Ginger Extracts Using an Agilent 6460 Triple Quadrupole LC/MS system with Triggered MRM

Importance of the Topic

The growing demand for safe agricultural products and compliance with strict regulatory maximum residue limits (MRLs) requires sensitive and accurate methods for pesticide analysis in complex matrices such as chamomile and ginger extracts.

Objectives and Study Overview

This study demonstrates the application of triggered multiple reaction monitoring (tMRM) on an Agilent 6460 Triple Quadrupole LC/MS system, coupled to an Agilent 1290 LC, for the simultaneous identification and quantitation of 51 pesticides in chamomile and ginger extracts. The focus was on preventing false positive identifications of tebuthiuron in chamomile and tebufenpyrad in ginger.

Methodology and Instrumentation

Sample preparation followed a QuEChERS protocol using acetonitrile extraction, dispersive SPE cleanup with MgSO4, PSA, and graphitized carbon black (for chamomile), and acid stabilization. Chromatographic separation employed a ZORBAX Eclipse Plus C-18 RRHD column (100×2.1 mm, 1.8 µm) with a gradient of 5 mM ammonium formate in water (A) and methanol (B) at 0.5 mL/min. The Agilent Jet Stream interface in positive/negative modes provided drying gas, sheath gas, and optimized voltages. tMRM acquisition triggered up to 10 MRM transitions per analyte, maximizing dwell times and capturing full product-ion spectra for library matching.

Key Results and Discussion

In chamomile extract, an endogenous compound exhibited a 3.18 % retention time shift and a qualifier/quantifier ion ratio of 189.9 % relative to tebuthiuron, exceeding SANCO tolerances. tMRM library matching unequivocally excluded tebuthiuron in blank extracts, while spiked standards yielded linear calibration (1–100 ng/mL, R²=0.9997) and precision (%RSD ≤1.1 %). In ginger, a co-eluting matrix interference shared primary MRM transitions with tebufenpyrad but produced a low library match score (70.34/100) when compared to the tebufenpyrad library spectrum, preventing false positives.

Benefits and Practical Applications

• Delivers quantitative data and confirmatory spectra in a single injection
• Enhances sensitivity and specificity over conventional MRM
• Mitigates false positives in complex herbal matrices, aiding regulatory compliance

Future Trends and Applications

Triggered MRM is poised to become a standard tool for high-throughput pesticide residue screening. Advances in real-time data processing, expanded spectral libraries, and faster instrumentation will further improve confidence and throughput in food safety laboratories.

Conclusion

tMRM acquisition on a triple quadrupole LC/MS platform provides a robust, sensitive, and specific workflow for identifying and quantifying pesticide residues in challenging botanical extracts, effectively preventing false positives and ensuring adherence to regulatory requirements.

References

1. Regulation (EC) No 396/2005 of the European Parliament and of the Council of 23 February 2005 on maximum residue levels of pesticides in or on food and feed of plant and animal origin, including amendments to 18 March 2008.
2. European Guideline SANCO/10684/2009: Method validation and quality control procedures for pesticide residue analysis in food and feed.
3. Official collection of test procedures according to § 64 LFGB, Beuth-Verlag.