Nafion covered core–shell structured Fe3O4@graphene nanospheres modified electrode for highly selective detection of dopamine

Schematic illustration of the reaction mechanism of Fe3O4@GNs/Nafion with DA. [Display omitted] •The sensor based on Fe3O4@graphene nanospheres was prepared for the first time.•The biosensor shows a wide linear range and a lower detection limit of 0.007μM.•This method was successfully applied to detection of DA in real samples. Nafion covered core–shell structured Fe3O4@graphene nanospheres (GNs) modified glassy carbon electrode (GCE) was successfully prepared and used for selective detection dopamine. Firstly, the characterizations of hydro-thermal synthesized Fe3O4@GNs were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. Then Fe3O4@GNs/Nafion modified electrode exhibited excellent electrocatalytic activity toward the oxidations of dopamine (DA). The interference test showed that the coexisted ascorbic acid (AA) and uric acid (UA) had no electrochemical interference toward DA. Under the optimum conditions, the broad linear relationship was obtained in the experimental concentration from 0.020μM to 130.0μM with the detection limit (S/N=3) of 0.007μM. Furthermore, the core–shell structured Fe3O4@GNs/Nafion/GCE was applied to the determination of DA in real samples and satisfactory results were got, which could provide a promising platform to develop excellent biosensor for detecting DA.