Evaluation of a Graphite-Polyurethane Composite Electrode Modified with Copper Nanoparticles as an Amperometric Flow Detector in a Wall-Jet System for the Determination of Cysteine

Autor(es)

Mattioli, Isabela A. ^[1] ; Schildt, Leticia F. L. ^[1] ; Cervini, Priscila ^[1] ; Saciloto, Thalita R. ^[1] ; Cavalheiro, Eder T. G. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Quim Sao Carlos, Av Trabalhador Sao Carlene 400, BR-13566590 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of the Brazilian Chemical Society; v. 31, n. 2, p. 370-380, FEB 2020.
• Citações Web of Science: 0

Resumo

A graphite-polyurethane composite electrode (GPUE) was modified by electrodeposition of copper nanoparticles (CuNP) followed by electrochemical treatment in NaOH (GPUE-CuNP), in order to prepare an amperometric sensor for the determination of cysteine (Cys). Cyclic votammograms of Cys solutions at GPUE-CuNP allowed the description of a sequence of electrochemical reactions involving Cys oxidation and Cu/Cu+ equilibrium, generating a stable Cys-Cu+ complex. The presence of these nanoparticles was confirmed by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) data. Hence, the developed device was then used as a Cys amperometric flow detector in a wall-jet system, after evaluation of flow injection parameters in an undescribed approach. In this system, a limit of detection (LOD) of 4.24 µmol L-1 was obtained with an analytical frequency of 36 determinations h-1. Intra-day and inter-day reproducibility and repeatability of the modified surface was evaluated. Then the GPUE-CuNP performance was investigated in the determination of Cys content in food supplements. Interference tests were carried out with pyridoxine, ascorbic acid, tryptophan and SO4 2- ions. The main interference was attributed to the interaction of some of these substances with copper oxides. (AU)

• Processo FAPESP: 18/11071-0 - Desenvolvimento e aplicação de eletrodos compósitos impressos descartáveis à base de nanopartículas metálicas e grafite-poliuretana
• Beneficiário: Isabela Alteia Mattioli
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto
• Processo FAPESP: 17/04211-7 - Desenvolvimento de tintas à base de nanopartículas metálicas e polímeros para construção de eletrodos compósitos convencional e impresso e suas aplicações
• Beneficiário: Éder Tadeu Gomes Cavalheiro
• Modalidade de apoio: Auxílio à Pesquisa - Regular