Analytical Method for Detecting Herbicides, Plant Growth Regulators, and Fungicides in Agricultural Commodities: Single-Laboratory Validation.

Abstract

Background: Pesticide residue analysis is a critical component of food safety monitoring. While multiresidue methods based on LC- or GC-MS are widely available, the analysis of highly polar or ionic pesticides remains challenging due to poor chromatographic retention, low recoveries, and repeatability.

Objective: This study aimed to develop a simple, rapid, and robust analytical method for the determination of highly polar or ionic pesticides and their metabolites in selected agricultural commodities.

Methods: The method targets herbicides, including glyphosate, aminomethylphosphonic acid, glufosinate, 3-methylphosphinicopropionic acid, and N-acetyl-glufosinate, the plant growth regulator ethephon, and a fungicide, fosetyl-Al, and its metabolite phosphonic acid. Sample preparation involved acidified methanolic extraction without cleanup or derivatization. Analysis was performed using LC coupled with tandem mass spectrometry (MS/MS). Chromatographic conditions were optimized to achieve baseline separation of all target analytes.

Results: The method demonstrated satisfactory performance across fruit matrixes including apple, orange, tomato, cucumber, watermelon, and strawberry. Recoveries ranged from 79 to 103%, with precision values below 13% at all levels tested. The method achieved low matrix effects and met the maximum residue levels established for the target analytes in the respective commodities.

Conclusion: The developed method provides a reliable and efficient approach for the analysis of highly polar pesticides and their metabolites in agricultural commodities, addressing limitations associated with conventional multiresidue methods.

Highlights: An analytical method was developed for the determination of highly polar and ionic pesticides that are traditionally challenging to analyze. The method employs a simple sample preparation approach, enabling higher analytical throughput. Validation results demonstrated satisfactory performance as per the the analytical quality control requirements outlined in the SANTE/11312/2021 (V2) guidelines. The method complies with national (FSSAI) as well as international (EU) maximum residue limits.