Highly Sensitive Voltammetric Sensor for Nanomolar Dopamine Detection Based on Facile Electrochemical Reduction of Graphene Oxide and Ceria Nanocomposite

In this study, a new electrochemical sensor was fabricated and characterized based on a glassy carbon electrode (GCE) modified with ceria (CeO2) nanoparticles decorated with electrochemical reduced graphene oxide (denoted as Ceria-ErGO/GCE). The results showed that a large number of spherical ceria nanoparticles with a diameter of 20-200 nm are well wrapped by gossamer like ErGO nanosheets. Compared with ceria and ErGO, ceria-ErGO nanocomposites have a synergistic effect on the charge transfer between the electrode and the solution interface. Ultrasensitive and selective determination of dopamine (DA) can be realized at the Ceria-ErGO/GCE. Under the optimum conditions, the calibration curve for the peak current of DA oxidation vs its concentration showed in three fragmented ranges of 6.0 nM-0.1 mu M; 0.1 mu M-2.0 mu M and 2.0 mu M-20 mu M, respectively. The limit of detection of 3.0 nM (S/N = 3) was obtained under 90 s accumulation. In addition, the advantages of the sensor are easy regeneration of electrode surface, fast and convenient electrode preparation, low cost, sensitive and reliable determination results. This method is particularly suitable for the fast detection of DA in commercial pharmaceuticals and clinical urine as well as serum samples.