CONICET | Buscador de Institutos y Recursos Humanos

Glyphosate (N-phosphonomethyl glycine) is a broad spectrum, non-selective, post-emergent herbicide, extensively used in many countries along with other chemical tools such as ammonium glufosinate [ammonium (S) -2-amino-4- (hydroxyl (methyl) phosphinoyl) butyrate]. Glyphosate degrades rapidly in its metabolite AMPA (aminomethyl-phosphonic acid). The growing use of crops resistant to herbicides, in particular to glyphosate, has generated concern about environmental quality, food safety and consumer health. Despite of the increasing use of these herbicides, its effect on "non-target" organisms have not yet been fully evaluated. The large volumes of herbicides employed and the growing trend on its uses in future lead to the need of increasing and improving the control of impacts they cause. Reliable, simple and sensitive analytical methods are needed. These analytes are polar and amphoteric compounds, properties that complicate its extraction, chromatography, and detection in different matrices. This work presents a simple and rapid method for the determination of glyphosate, its metabolite AMPA and glufosinate ammonium in serum samples by UHPLC-MS/MS. The method consists in a first step of precipitation of proteins with acetonitrile and then a derivatization with 9-fluorenilmethylchloroformate (FMOC-Cl), a reaction that is carried out at room temperature for 2 hours (1), followed by liquid-liquid extraction with dichloromethane as the cleanup step. Satisfactory results have been obtained, showing that this method is consistent and reliable, with low RSDs and good recovery between 90-130% in two levels of concentration (LOQ and 10 µg/L) and LOD of 1 µg/L. Applications were made in experimental studies with animals. This simplified method showed advantages in comparison with existing approaches, contributing to the challenge of measuring glyphosate and related analytes in simpler, economical and reliable ways.

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