Synthesis and Characterization of Bentonite-Reduced Graphene Oxide Composite: Application as Sensor for a Neurotransmitter, Dopamine

Abstract

Bentonite (Bent)-graphene oxide (GO) thin film coated on glassy carbon electrode (GCE) was prepared and employed as a sensor for a neurotransmitter, dopamine (DA). Bent-GO suspension was drop casted on GCE and subjected to electro-reduction(Er) in the potential range of 0.6 to −1.7 V. DA exhibited redox peaks with peak-peak separation of ∼190 mV at bare GCE. However, significant enhancement in the redox peak current and decreased potential in the peak-peak separation (∼140 mV) was observed for DA at Bent-ErGO/GCE. Electrochemical investigations on DA at the proposed sensor indicated the involvement of equal number of electrons and protons in the electrode reaction. Further, the electrode processes were found to be diffusion and adsorption controlled for anodic and cathodic peak, respectively. Under optimized conditions, a linear relationship was noticed between the peak current and concentration of DA in the range of 0.5–50 μM and 0.1–40 μM using differential pulse voltammetric and chronoamperommetric methods respectively. The applicability of the proposed sensor was efficiently demonstrated by analyzing the pharmaceutical and biological samples containing DA. Higher recovery values (more than 97.85%) and lower RSD values (less than 2%) highlighted the accuracy and precision of the proposed analytical method.