Sensor eletroquímico para monitoramento do agrotóxico imidacloprido em águas naturais

Abstract

The rapid population growth along with the consequent food demand increase have been pushing up the primary economy sectors efforts for achieve the global alimentation necessary. Nevertheless, the persistent use of agrochemicals and the inattention of dosages have been conducting to a contaminated environment, especially water resources, offering health and environmental risks. The objective of the present study was to develop an electrochemical sensor for rapid, in situ quantification, without prior sample preparation, of the insecticide imidacloprid in natural water samples. The experimental design used was the Central Composite Rotational Design (CCRD) to optimize the parameters: frequency, amplitude and scan increment, totaling 17 tests. The cyclic and square wave voltammetry techniques were used to characterize the working electrode and quantify the agrochemical. The analytical results of the sensor, in the analyses of imidacloprid in a natural sample, were compared with the analyses using UV-Vis spectroscopy. The optimized parameter values were 55Hz, 43mV and 5mV, respectively. Analyzes using the electrochemical sensor indicated LD of 1.49∙10-11 mol L-1 and LQ of 4.96∙10-11 mol L-1. Imidacloprid was detected in real samples with R2 of 0.994 and recovery of 98.94%, demonstrating the effectiveness of the sensor for use in natural waters. The spectroscopic method, with which the sensor was compared, obtained R2 of 0.997 and 99.74% recovery. Therefore, it is concluded that EAu can be used to detect imidacloprid in natural waters without prior sample preparation and without altering its surface. There is also the prospect of miniaturizing the sensor to use it in situ for real-time environmental monitoring. There is also the prospect of miniaturizing the sensor to use it in situ for real-time environmental monitoring. The expectation is that, through this work and future work, we will contribute to increasing the development of Brazilian technologies and innovations related to sensors for environmental purposes.