Sensor eletroquímico descartável para detecção de glifosato aplicado no campus Lagoa do Sino da UFSCar

Abstract

Due to the panorama of intensive consumption of pesticides in Brazil, the environmental impacts linked to the transportation, pollution and contamination of ecosystems by such compounds stand out, whose effects can present, in many situations, considerable adversity to environmental and human health. The non-selective herbicide glyphosate is the most widely used pesticide in the world and is presented in several studies as a contaminant of water bodies, so that methods that seek to detect it in environmental contexts are pertinent, especially through quick and simple strategies. In this sense, electrochemical sensors are advantageous due to the versatility of miniaturization and ease of operation, with emphasis on the applicability of disposable printed electrodes in the detection of various types of analytes. Thus, the present work consisted of developing a disposable electrochemical sensor, using screen printed gold electrodes, to detect glyphosate in real water samples, which were collected in water bodies near rainfed agriculture areas of the Lagoa do Sino campus of the Federal University of São Carlos, where the herbicide was sprayed. In addition, samples of rainfed plants were collected and washed with distilled water to verify the presence of the herbicide and evaluate the performance of the sensor in this situation. For this purpose, screen printed gold electrodes were employed using the square wave voltammetry technique in a linear range from 0.1 to 10 μmol L−1 of the herbicide with a detection limit of 0.057 μmol L−1. The tests of water samples from the lakes showed current increases precisely in the oxidation potential of glyphosate (0.8V), comparing the samples collected before and after spraying of the pesticide, which suggests that there was drift and pollution of water bodies. In addition, a significant signal of glyphosate was obtained in the water sample referring to the washing of the surface of the plants, attesting to the efficiency of the electrochemical sensor in the detection of the herbicide.