| Texto completo | |
| Autor(es): Mostrar menos - |
de Oliveira, Thawan G.
;
Chioquetti, Rafael A. L.
;
Cappelletti, Jessica L. M.
;
Martins, Douglas A. M.
;
Vendruscolo, Victor
;
Goncalves, Josue M.
;
Souza, Rodrigo S.
;
Nogueira, Helton P.
;
Araki, Koiti
;
Angnes, Lucio
;
Serrano, Silvia H. P.
;
Bacil, Raphael P.
Número total de Autores: 12
|
| Tipo de documento: | Artigo Científico |
| Fonte: | Electrochimica Acta; v. 545, p. 12-pg., 2025-11-11. |
| Resumo | |
The electrochemical oxidation of the diuretic indapamide (IND) was investigated in detail using cyclic and square wave voltammetry at a glassy carbon electrode (GCE). Three distinct oxidation processes were identified across a wide pH range. At pH 12, the first two processes were electrochemically reversible and occurred sequentially, with the first one involving one-electron and one-proton transfer, and the second being a one-electron and a proton-independent step. Both steps were followed by fast homogeneous chemical reactions that influence the voltammetric response and surficial behavior. A pH-driven potential inversion was observed, leading to the merge of Processes 1 and 2 into a single two-electron oxidation wave under acidic conditions. Quantum chemical calculations confirmed the structural and electronic changes across the redox sequence, which corroborated the proposed mechanism. Adsorption of IND onto GCE was found to occur more extensively in acidic media, due to its neutral molecular form at low pH. These mechanistic insights enabled the rational optimization of an electroanalytical method for its detection. Due to both adsorption and multi-electron transfer, the square wave voltammograms at pH 2.0 yielded a significant enhancement of the faradaic response, resulting in a higher sensitivity, although with lower reproducibility compared to pH 12. This study highlights the critical role of mechanistic elucidation in the design of robust, sensitive, and selective electrochemical detection strategies, particularly for pharmaceutical and anti-doping applications. (AU) | |
| Processo FAPESP: | 18/16896-7 - Desenvolvimento de sensores amperométricos e impedimétricos baseados em hidróxidos duplos de níquel e Vanádio (alfa-NixV1-x(OH)2) e seus nanocompósitos com grafite expansível/grafenos |
| Beneficiário: | Josué Martins Gonçalves |
| Modalidade de apoio: | Bolsas no Brasil - Pós-Doutorado |
| Processo FAPESP: | 14/50867-3 - INCT 2014: Instituto Nacional de Ciência e Tecnologia de Bioanalítica |
| Beneficiário: | Marco Aurelio Zezzi Arruda |
| Modalidade de apoio: | Auxílio à Pesquisa - Temático |
| Processo FAPESP: | 19/22126-2 - Comportamento eletroquímico de hemiésteres do ácido carbônico em meio aquoso |
| Beneficiário: | Berlane Gomes Santos |
| Modalidade de apoio: | Bolsas no Brasil - Doutorado |
| Processo FAPESP: | 17/13137-5 - Formação e propriedades de hemiésteres do ácido carbônico em meio aquoso |
| Beneficiário: | Claudimir Lucio Do Lago |
| Modalidade de apoio: | Auxílio à Pesquisa - Temático |
| Processo FAPESP: | 24/20204-4 - Bases purínicas - estudo eletroquímico e desenvolvimento de modelos para descrever reações eletroquímicas acopladas a processos enzimáticos em solução |
| Beneficiário: | Rafael Alessandro Chioquetti de Lima |
| Modalidade de apoio: | Bolsas no Brasil - Doutorado Direto |