Pesticide Analysis in Unique Commodities using the Agilent 6470 Triple Quadruopole LC/MS System

Importance of the Topic

The occurrence of pesticide residues in commodities such as coffee, ginger, turmeric and pepper poses significant analytical challenges due to their complex composition of pigments and phytochemicals. Reliable monitoring is essential for food safety, regulatory compliance and consumer protection. Developing a sensitive and robust analytical method for these matrices addresses matrix-induced ion suppression or enhancement and ensures accurate quantitation at low residue levels.

Objectives and Study Overview

This study describes the development and partial validation of a liquid chromatography–tandem mass spectrometry (LC-MS/MS) method using dynamic multiple reaction monitoring (dMRM) on the Agilent 6470 triple quadrupole system. The goal was to quantify over 250 pesticide residues in dehydrated and pigmented commodities—coffee beans, dried ginger, turmeric and black pepper—by implementing a streamlined QuEChERS-based sample preparation and automated data review workflow.

Methodology and Instrumentation

Sample Preparation:

• Grinding and homogenization of whole coffee, ginger, turmeric and pepper samples.
• QuEChERS extraction with acetonitrile, water and dispersive SPE cleanup.
• Final extract diluted fivefold (acetonitrile:water 60:40) to mitigate matrix effects.
• Spiking at 10 ppb for recovery studies; matrix-matched calibration from 0.1 to 50 ng/mL (1/x weighting).

Used Instrumentation

• Agilent 1290 Infinity II LC system: high-speed pump, multisampler and multicolumn thermostat.
• Agilent ZORBAX RRHD Eclipse Plus C18 column (150 × 3.0 mm, 1.8 µm).
• Agilent 6470 triple quadrupole LC/MS with AJS-ESI source in positive mode.
• MassHunter software for acquisition (v10.1) and quantitative analysis (v10.1) with automated MRM ion ratio checks.

Main Results and Discussion

• Limits of detection (LOD) and quantification (LOQ) at 0.1 and 0.2 ng/mL for most analytes.
• Calibration curves exhibited linearity (R² > 0.995) across the tested range.
• Recovery studies showed 54.5 % to 111 % recovery, demonstrating acceptable accuracy.
• Reproducible peak shapes and retention times confirmed by overlaid triplicate chromatograms for each commodity.
• Real sample analysis detected chlorpyrifos, carbendazim, imidacloprid, metalaxyl and other pesticides at ng/g levels in coffee, turmeric, ginger and pepper.

Benefits and Practical Applications

• High sensitivity and selectivity enable trace-level detection in challenging matrices.
• Dilution strategy effectively reduces matrix effects without compromising MRL compliance.
• Automated scheduling of MRM segments maximizes data points across chromatographic peaks for reliable integration.
• Built-in ion ratio checks and batch-at-a-glance features streamline data review and minimize false positives.
• Suitable for routine QA/QC and regulatory testing laboratories handling diverse food commodities.

Future Trends and Potential Applications

• Integration of high-throughput sample processing and microflow LC to increase lab productivity.
• Advances in AI-driven data processing to automate peak identification and anomaly detection.
• Expansion of pesticide databases and spectral libraries for broader compound coverage.
• Application of hybrid instruments (e.g., Q-TOF) for non-targeted screening in complex food matrices.

Conclusion

This work demonstrates a robust, dMRM-based LC-MS/MS method on the Agilent 6470 system for accurate quantitation of over 250 pesticide residues in complex dehydrated commodities. The combination of QuEChERS extraction, sample dilution, optimized chromatography and automated data analysis provides a reliable workflow for routine monitoring of pesticide residues in coffee and spices.

Reference

• Sheshadri A.; Glauner T.; Faye T. Multiclass Determination of Organic Contaminants in Red Chili and Turmeric Powders. Agilent Technologies application note 5991-8243EN, 2017.
• Stone P.J.W. et al. Determination of Pesticides and Mycotoxins in Cannabis Flower as Defined by Legalized U.S. State Recreational Cannabis Regulations. Agilent Technologies application note 5994-1734EN, 2020.
• Zou A. et al. Comprehensive LC/MS/MS Workflow of Pesticide Residues in Food Using the Agilent 6470 Triple Quadrupole LC/MS System. Agilent Technologies application note 5994-2370EN, 2020.