Determination of quercetin in a pharmaceutical sample by square-wave voltammetry using a poly(vinylpyrrolidone)-modified carbon-paste electrode

• Autor(a) principal: Piovesan,Jamille V.
• Data de Publicação: 2014
• Outros Autores: Spinelli,Almir
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Journal of the Brazilian Chemical Society (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532014000300015
• topic: quercetin; carbon-paste electrode; poly(vinylpyrrolidone); electroanalysis

A carbon-paste electrode modified with the polymer poly(vinylpyrrolidone) was evaluated through electrochemical studies and the electroanalytical determination of quercetin. For this electrode, cyclic voltammograms of quercetin showed three oxidation peaks at +0.32, +0.78 and +1.04 V. The electro-oxidation associated with the first peak leads to the formation of the corresponding ortho-quinone, which can be reduced under favorable experimental conditions. Under such conditions, the reaction is quasi-reversible and the process is diffusion-controlled. This behavior was exploited for the electroanalytical determination of quercetin by square-wave voltammetry. The calibration curve was linear in the concentration range of 0.5 to 5.5 µmol L-1 (R² = 0.998). The limits of detection and quantification obtained were 0.17 µmol L-1 and 0.52 µmol L-1, respectively. The sensor was successfully used for the determination of quercetin in a pharmaceutical sample. The accuracy of the results achieved with the sensor was evaluated through comparison with the results provided by the UV-Vis technique.