LC-FLD Determination of Glyphosate, AMPA and Glufosinate in Surface Water from the Paraná River Basin

Abstract

Natural waters from the Paraná River hydrographic basin in the Brazil-Paraguay cross-border region were analyzed by liquid chromatography coupled to a fluorescence detector (LC-FLD) after extraction of the analytes in anion exchange resin IRA-900. The method allowed good recovery (91 to 113%) of the studied species (glyphosate, (aminomethyl)phosphonic acid (AMPA) and glufosinate) precision compatible with the requirements of the National Metrology Institute (relative standard deviation < 18%) and limit of quantification (LOQ) values between 0.2 and 0.8 mg L-1. In most of the samples collected between January and September 2022, it was impossible to detect the presence of herbicides, even in regions of intense agricultural activity, probably due to the high adsorption capacity of the soils of the region and due to the higher LOQ of the method. Under these conditions, the main transport route is estimated to be associated with surface runoff, which is only favored by heavy rainfall events.