New Clean-Up Method for Pesticide Analysis in Food

Ensuring that pesticide levels do not rise above the acceptable limits is important for guaranteeing that food products are safe for human consumption and that crops are harvested at their most optimal condition.

A recent study published in Analytical and Bioanalytical Chemistry explored this very issue. Using a new clean-up method involving micro solid-phase extraction (µSPE) to improve pesticide analysis in food, lead author Andreas Schürmann and his team at the Cantonal Laboratory Zürich developed an automated procedure utilizing µSPE cartridges on an x,y,z robotic sampler for raw extract clean-up and sample preparation for injection on a gas chromatography–tandem mass spectrometry (GC–MS/MS) system (1).

Generic extraction methods have long been utilized for multi-compound pesticide analysis, with ethyl acetate and acetonitrile extraction methods emerging as fast and easy-to-handle standards (1). However, challenges arise during direct injection to GC because of high coextracted matrix burdens, leading to chromatographic system deterioration and matrix effects necessitating frequent maintenance (1).

To address these issues, common clean-up methods such as dispersive solid-phase extraction, freeze-out of fats, or gel permeation chromatography were used (1). However, using micro-solid-phase extraction (µSPE) has shown several advantages in analyzing pesticides and contaminants in foods extracted with acetonitrile, yet its efficacy with ethyl acetate extraction remains unexplored. This study explored using µSPE in automated clean-up.

The team’s automated procedure used µSPE cartridges on an x,y,z robotic sampler for raw extract clean-up and sample preparation for injection on a GC–MS/MS system (1). Validation experiments encompassing 212 pesticides, polychlorinated biphenyls, and polycyclic aromatic hydrocarbons across various food extracts including lettuce, avocado, raspberry, paprika, egg, and liver were conducted using µSPE with MgSO₄, PSA, C18, and CarbonX (1).

The results showcased the effectiveness of the µSPE method in significantly reducing matrix effects and enhancing the sensitivity and accuracy of pesticide analysis in food samples. The automated clean-up method not only streamlines the analytical process but also minimizes the need for frequent maintenance of chromatographic systems, thus saving time and resources in laboratory settings (1).

µSPE showcased its potential for being used in routine pesticide analysis. The research team demonstrated in their study that µSPE has a key role to play in pesticide analysis moving forward.

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Reference

(1) Schürmann, A.; Cruzer, C.; Duss, V.; et al. Automated Micro-Solid-Phase Extraction Clean-up and Gas Chromatography–Tandem Mass Spectrometry Analysis of Pesticides in Foods Extracted with Ethyl Acetate. Anal. Bioanal. Chem. 2024, 416, 689–700.