Determinação electromagnetically e estudo eletroquímico de bentazon e fenamifós utilizando eletrodos de diamante

• Autor(a) principal: Lima, Thays de Souza [UNIFESP]
• Data de Publicação: 2017
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UNIFESP
• Texto Completo: https://sucupira.capes.gov.br/sucupira/public/consultas/coleta/trabalhoConclusao/viewTrabalhoConclusao.jsf?popup=true&id_trabalho=5005984; http://repositorio.unifesp.br/handle/11600/50040
• topic: Bentazon; Fenamiphos; Electrochemistry; Extensive electrolysis; Chemometrics; Bentazon; Fenamifós; Eletroquímica; Eletrólises exaustivas; Quimiometria; Eletrodo de diamante dopado com boro

This study aimed to develop an electroanalytical methodology for determination of bentazon (BTZ) and fenamiphos (FNP) and also the electrochemical study these pesticides by exhaustive electrolysis. The BTZ presented a single oxidation peak in +1.01 V vs Ag / AgCl, and theFNP presented a single oxidation peak at + 1.18 V vs Ag / AgCl, both with irreversible process characteristics and controlled by diffusion. To develop the methodology for quantification of pesticides has used square-wave voltammetry (SWV). The analytical curves were obtained in concentration range of 9.90x10-6 mol L-1 to 9.09x10-5 mol L-1. For the BTZ the detection limits (LOD) and quantification (LOQ) values were 3.00x10-6 mol L-1 and 9.90x10-6 mol L-1, respectively. For the FNP, the LOD and LOQ values were 1.50x10-6 mol L-1 and 4.98x10-6 mol L-1, respectively. The performance of the developed method was evaluated by recovery studies in natural water samples and showed recovery percentages of 98.0% and 109.2% for BTZ and FNP, respectively. Was also developed a method for the simultaneous and selective determination of BTZ and FNP, the best results were obtained using square wave voltammetry and chemometric methods with of a 33 factorial full design. With selected parameters an analytical curve was constructed in the concentration range of 9.90x10-6 mol L-1 to 9.09x10-5 mol L-1 for the mixture of BTZ and FNP. For BTZ the values of LOD and LOQ were 3.80 x 10-7 mol L-1 and 1.27 x 10-6 mol L-1, respectively. For FNP the LOD and LOQ values were 3.00 x10-6 mol L-1 and 9.90x10-6 mol L-1, respectively. The study of destructive oxidation on the boron-doped diamond (BDD) electrodes for pesticides was realized using electrolysis at controlled potential. The electrolysis monitoring with the square wave voltammetry techniques, absorption spectrometry in the UV- Visible, total organic carbon (TOC) analyzes, and liquid chromatography with mass detector (LC-MS). An initial concentration of the pesticides decay of the electrolysis course. The percentages initial decreasing around 50.7 % for BTZ and 55.0 % for FNP.