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

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.