Determination of Quercetin by a Siloxane-Polyester/Poly-L-Lysine Nanocomposite Modified Glassy Carbon Electrode

• Autor(a) principal: Pereira, Elaine Renata de Castro Viana [UNESP]
• Data de Publicação: 2016
• Outros Autores: Bessegato, Guilherme Garcia [UNESP], Yamanaka, Hideko [UNESP], Zanoni, Maria Valnice Boldrin [UNESP]
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.1080/00032719.2015.1104323; http://hdl.handle.net/11449/172987
• topic: Catechol; poly-L-lysine; polysiloxane-poly(propylene) oxide polymer; quercetin; voltammetric sensor

Poly-L-lysine incorporated in the nanocavities of polysiloxane-poly(propylene) oxide is reported as an electrochemical sensor for quercetin. A glassy carbon electrode coated by poly-L-lysine/polysiloxane-poly(propylene) oxide accumulated quercetin through hydrogen bonding in pH 2 ethanol/Britton-Robinson buffer. The catecol oxidation was monitored at 0.45 V as a reversible two electron peak. The voltammetric response using the film electrode was 80% higher compared to a bare electrode. Square wave voltammetry was employed using an accumulation time of 8 min and a linear relationship was obtained for concentrations of quercetin from 1.0 × 10−8 mol L−1 to 1.0 × 10−6 mol L−1. The limit of detection was 2.76 ± 0.5 × 10−9 mol L−1. The method was employed to determine quercetin in green tea, but did not show selectivity to catechin, which was oxidized at a similar potential. The measurements were validated by high-performance liquid chromatography.