Simultaneous Determination of Glyphosate, Aminomethylphosphonic Acid, and Glufosinate in Green Coffee Beans by LC-MS/MS: Optimization, Validation, and Field Study

Despite the widespread use of glyphosate in coffee crops, there is a lack of simple, low-cost, validated methods for detecting glyphosate and related compounds in green coffee beans, the primary export form subject to international regulation. This study optimized and validated a liquid chromatography with tandem mass spectrometry method for the determination of glyphosate, aminomethylphosphonic acid (AMPA), and glufosinate in green coffee, using a modified QuPPe-PO extraction followed by a cleanup combining liquid-liquid extraction and dispersive solid-phase extraction. Validation followed SANTE/11312/2021 guidelines, confirming the method's linearity, precision, accuracy, and quantification limits. Limits of quantification were 0.02 mg kg^-1 (glyphosate), 0.04 mg kg^-1 (AMPA), and 0.01 mg kg^-1 (glufosinate). The method was applied to a field study with Arabica coffee and Conilon Coffee, revealing that plant height was the primary factor influencing residue levels. The proposed method enables reliable monitoring of polar herbicides in coffee without the need for derivatization.