Chemically Reduced Graphene Oxide on Gold Electrodes from Recordable CDs: Characterization and Potential Sensing Applications

Abstract

This work presents the development and characterization of a new chemically modified electrode exploiting recordable Au-rewritable compact discs (AuCDs) as substrate for drop casting of a chemically-reduced graphene-oxide slurry focusing on simple and low-cost electrochemical sensors. Increase in electrochemical responses in cyclic voltammetric and amperometric measurements were achieved using the proposed sensor. Both scanning electron microscopy and atomic force microscopy data showed increase in rugosity (about 46% higher) for the chemically reduced graphene oxide (CRGO) AuCD surface while Raman spectroscopy confirmed the presence of structural defects of graphene. The calculated charge transfer resistances (R ct) and heterogeneous electron transfer rate constants (k 0) were 1638 Ω and 0.0022 cm s-1 for the bare substrate, and 91 Ω and 0.0027 cm s-1 for the modified electrode, evidencing the facilitated electron transfer of the CRGO-AuCD surface. The dopamine (DP) amperometric detection using CRGO-AuCD provided low detection limit (0.12 µg L-1) compared with other modified electrodes already reported, high precision (relative standard deviation (RSD) < 5%) and analytical frequency (370 h-1). As a proof-of-concept, DP determination in synthetic saliva samples was performed and a satisfactory recovery value (98.6 ± 0.9%) was obtained.

Synthesis and Application of Heteroatom-Doped Graphite as the Electrode Material: Influences of Defect Density and Heteroatom on Heterogeneous Electron Transfer Rate

“…22−24 It has been shown that in carbonous materials, the edge plane is extremely more reactive than the basal plane and facilitates the rate of HET. The basal plane contains carbon with sp 2 hybridization; it is flat with low defect density, while the edge plane contains sp 3 sites, functional groups, dangling bonds, and defects due to the abrupt lattice termination. The electrochemical activity of the basal plane is very low and depends on the history and the number of defects on the surface.…”

“…Carbonous materials have been extensively used for the fabrication of various electrodes/sensors/biosensors compared to other materials because of their appropriate chemical inertness, wide potential window, great mechanical resistance, flexible surface modification, and cost-effectiveness. − It is well known that the rate of heterogeneous electron transfer (HET) at the interface of carbonous electrode and electrolyte solution mainly depends on defect density, type of defect, and morphology (grain boundaries) of the carbonous materials. These factors also play a remarkable role in the selectivity and performance of the redox reactions, electrocatalytic reactions, sensing, etc. − The difference in the rate of HET in many studies has been attributed to the difference in electrode morphology as the main factor, which can be easily explored and compared .…”

Desenvolvimento de métodos eletroanalíticos utilizando sensor a base de grafeno para a determinação de antibióticos em amostras de leite e formulações farmacêuticas

“…O processo de modificação por adsorção vem sendo bastante utilizado para incorporar dispersões de rGO em diferentes substratos eletroquímicos. Em grande parte dos trabalhos reportados na literatura, são observadas modificações estáveis com baixa dessorção do modificador, possibilitando obter uma boa reprodutibilidade do sinal analítico durante as análises (GAN et al, 2014;SILVA et al, 2020;VASCONCELOS et al, 2020). O método drop casting é o mais empregado para este propósito, em razão da simplicidade e baixo custo.…”