Método analítico para determinação de glifosato e AMPA e aplicação em amostras de água de cultivo hidropônico de mudas de eucalipto

Abstract

The indiscriminate use of chemicals has contributed to the contamination of organisms and ecosystems. Glyphosate-based herbicides are widely used due to their relatively low cost and excellent weeding efficiency. In addition to its high efficacy, this herbicide is classified as low toxic and rapidly converted to its main metabolite, Aminomethylphosphonic Acid (AMPA), although studies indicate possible deleterious effects on organisms and the environment. In this context, the objective of this work was to optimize and validate an analytical method for glyphosate and AMPA determination in water samples using solid phase extraction and detection by high performance liquid chromatography coupled to the inductively coupled plasma mass spectrometer (HPLC-ICP-MS/MS). Compounds were separated with a total analysis time of less than 5 minutes. The method was selective, not interfering with the retention time of the analytes and was linear. The limits of quantification of 1,09 µg L-1 for glyphosate and 0,29 µg L-1 for AMPA were below the maximum residue values defined by resolution CONAMA Nº 430 for the water courses. The method was precise and accurate, obtaining an average recovery of 99%± 0,99 for glyphosate and 98%± 5,41 for AMPA, and there was no matrix effect. The method was applied to water samples from hydroponic cultivation of eucalyptus seedlings, to verify if the exudation occurred. The results showed that glyphosate was detected in the samples, revealing sufficient sensitivity to detect glyphosate exudation by eucalyptus roots. In these samples, glyphosate from the exudation process was 1,38 to 1,54 µg L-1 of the analyte in the hydroponic solution.