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.; Schildt, Letícia F. L.; Cervini, Priscila; Saciloto, Thalita R.; Cavalheiro, Éder T. G.
FONTE
J. Braz. Chem. Soc.
DATA DE PUBLICAÇÃO
2020-02
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.
Documentos Relacionados
- Determination of paracetamol at a graphite-polyurethane composite electrode as an amperometric flow detector
- Graphite-Polyurethane Composite Electrode Modified with Molecularly Imprinted Polymer for Determination of Diclofenac
- Determination of tetracycline in environmental water samples at a graphite-polyurethane composite electrode
- Using of a graphite-polyurethane composite electrode modified with a Schiff base as a bio-inspired sensor in the dopamine determination
- Simultaneous voltammetric determination of acetaminophen and caffeine at a graphite and polyurethane screen-printed composite electrode