2019-05-032022-04-262022-04-262019-03-29CAIXETA NETA, A. Determinação eletroquímica do agrotóxico tiabendazol extraído e pré-concentrado em amostras de tomate pela técnica de ponto nuvem usando eletrodo de diamante dopado com boro. 2019. 101 f. Dissertação (Mestrado em Química) - Universidade Federal de Goiás, Catalão, 2019.http://repositorio.ufcat.edu.br/tede/handle/tede/9560In Brazil, there is a significant consumption of tomatoes and, according to the report of the Program of Analysis of the Residues of Agrochemicals in Food (PARA) available by ANVISA, the tiabendazole (TBZ) fungicide was detected in some tomato samples analyzed. The detection of this substance is considered to be prohibited, since the TBZ is authorized only for application in seeds of the plant and, therefore, could not be found in fruits. Thus, electrochemical methods can be used for the determination of pesticides in complex samples and in low concentration levels, because they produce fast and reliable measurements, consuming small amounts of reagents. In this work, a procedure for the electroanalytical determination of TBZ fungicide in tomato fruits using boron-doped diamond electrode (BDD) was developed and validated using the cloud extraction and preconcentration (CPE) technique. The analytical technique used in this determination was the High Performance Liquid Chromatography coupled to an electrochemical detector (HPLC-EC), by the use of the BDD electrode. In order to evaluate the main variables of the CPE process, it was used a 24 complete factorial planning to optimize the parameters. The CPE optimized condition was achieved by the use of Tergitol (19% V/V), NaCl (0.83 g), ultrasonic stirring time of 15 min and temperature of 36 °C. Under these conditions, the preconcentration factor obtained was 5.7. The limits of detection and quantification obtained were 2.7 × 10-8 mol L-1 and 5.5 × 10-8 mol L-1 , respectively. The average recoveries obtained in 3 days were satisfactory, varying between 80.7% and 115.1%, which demonstrates the good accuracy of the developed method. In the application of the method in commercial tomatoes, TBZ was detected in one of the samples analyzed. The differential pulse voltammetry (DPV) technique was also investigated for the electroanalytical determination of TBZ fungicide in tomato fruit (extracted and pre-concentrated by CPE) using BDD electrode in order to increase the analytical frequency. The use of DPV technique increased the analytical frequency by approximately 90 times compared to the HPLC/EC technique.application/pdfAcesso AbertoTiabendazolExtração por ponto nuvemCLAE/ECVPDEletrodo de diamanteThiabendazoleCloud oint extractionHPLC-ECDPVDiamond electrodeFISICO-QUIMICA::ELETROQUIMICADissertação