Desenvolvimento e aplicação de um eletrodo modificado com nanotubos de carbono na determinação voltamétrica do pesticida carbendazim em suco de laranja

• Autor(a) principal: Armani, Alynne Gabrielle Oenning
• Data de Publicação: 2022
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Biblioteca Digital de Monografias da UFMT
• Texto Completo: http://bdm.ufmt.br/handle/1/3227
• topic: CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA; Sensor eletroquímico; Eletrodo modificado; Nanotubos de carbono; Carbendazim; Electrochemical sensor; Modified electrode; Carbon nanotubes; Carbendazim

This work describes the development and application of an electrode modified with films of multi-walled carbon nanotubes (MWNTC) and chitosan for quantification of the fungicide carbendazim (CBZ) in orange juice, using a glassy carbon electrode (ECV) as electrode base. To make the modified electrode, 5 mg of chitosan and 2 mg of MWNTCs were added to 1 mL of 1% acetic acid solution (v/v) pH 5.0, taken to ultrasound and applied to the surface of the ECV. In the analytical application of the electrode for the determination of carbendazim, an irreversible oxidation peak was observed at +0.77 V, vs. Ag/AgCl, in 0.1 mol L-1 phosphate buffer (pH 7.0). The instrumental parameters of differential pulse voltammetry were optimized, and the best response in terms of sensitivity and selectivity was obtained by applying pulse amplitude (△Ep) of 100 mV, potential increment (Es) of 10 mV and pulse time ( tp) of 0.2s. The analytical curve was obtained in the concentration range from 1.0 to 25.0 mg L-1 (R2 = 0.99301), in 0.1 mol L-1 phosphate buffer solution, with detection limits (LD) of 0.230 mgL-1, and limits of quantification (LQ) of 0.698 mg L -1 . For the analysis of the real sample of CBZ in diluted commercial orange juice, the linear concentration range from 1.0 to 25 mg L-1 (R2 = 0.98945) was obtained, with higher detection and quantification limits reached, of 0.763 mg L1 and 2.310 mg L-1, respectively. The proposed method also provided repeatability and reproducibility measures with a relative standard deviation below 6%.