Ref.: MmeBi32-004
Apresentador: Lizz Gabi Luza
Autores (Instituição): Luza, L.G.(Universidade Federal do Rio Grande do Sul); Hass Costa, T.M.(Universidade Federal do Rio Grande do Sul); de Menezes, E.W.(Universidade Federal do Rio Grande do Sul); Benvenutti, E.V.(Universidade Federal do Rio Grande do Sul); Arenas, L.T.(Universidade Fedearl do Rio Grande do Sul);
Resumo:
Recently, metal oxide nanoparticles (NPs) have contributed to the development of efficient electrochemical sensors with good selectivity [1]. In this context, manganese ferrite (MFO) NPs with different crystallite sizes and morphology were obtained, carbon paste electrodes (CPE) were constructed with the NPs, and the dopamine (DA) response on the surface of the electrodes was evaluated.
MFO NPs were obtained by the coprecipitation and hydrothermal method, using Mn (II) and Fe (III) salts in a 1:2 ratio in basic medium. NPs were also prepared under similar conditions using beta cyclodextrin (CD) as a stabilizing agent, this sample was named CD-MFO.
Both samples showed magnetic properties. X-ray diffraction analysis of the NPs indicated the presence of manganese ferrite with a crystallite size of 25 nm for MFO and 5 nm for CD-MFO. The NPs showed high BET area values, contact angle measurements indicated that the MFO has a hydrophilic surface, however the CD-MFO has a hydrophilic surface.
Differential pulse voltammetry measurements of the modified CPE in the presence of DA indicated that the oxidation is 0.16 V for CPE MFO and -0.16 V for CPE CD-MFO. Interference analysis showed that the CD-MFO CPE is more selective for AD as no interference was observed from analytes such as ascorbic acid (AA), uric acid (UA), caffeine and glucose, however in the MFO CPE interference from AA and AU in DA response. The electrodes showed a linear range at low concentrations with good sensitivity. Therefore, the CPE modified with manganese ferrite NPS can be used as an electrochemical DA sensor.