Simultaneous electrochemical sensing of serotonin, dopamine and ascorbic acid by using a nanocomposite prepared from reduced graphene oxide, Fe3O4 and hydroxypropyl-β-cyclodextrin.

Reduced graphene oxide containing Fe3O4 nanoparticles was decorated with hydroxypropyl-β-cyclodextrin (HP-β-CD) to construct a novel nanocomposite (3D-rGO/Fe3O4/HP-β-CD). The composite was placed on a glassy carbon electrode (GCE) to design an electrochemical sensor for detecting simultaneously serotonin (5-HT), dopamine (DA), and ascorbic acid (AA). The interconnected porous reduced graphene oxide framework tightly anchored to the Fe3O4 magnetic nanoparticles warrants good electrical conductivity and efficient catalytic activity. The HP-β-CD acts as a supramolecular host with high recognition ability for 5-HT, DA and AA. Well-separated oxidation peaks and increased peak currents were observed for 5-HT, DA, and AA individually and in mixtures by differential pulse voltammetry (DPV). The following figures of merit were found for simultaneous electrochemical determination of 5-HT, DA, and AA: (a) Well separated peaks at around 0.316, 0.16 and - 0.044 V; (b) linear responses in the 0.01 - 25 μM, 0.02 - 25 μM and 10 - 350 μM; (c) detection limits of 3.3 nM, 6.7 nM and 3.3 μM (S/N = 3), and (d) recoveries of 96.9-103%, 97.3%-102% and 96.3-105% from spiked serum samples, respectively. All relative standard deviation (RSD) are less than 4%. Graphical abstractSchematic representation of simultaneous detecting serotonin (5-HT), dopamine (DA) and ascorbic acid (AA) for three-dimensional reduced-graphene oxide/Fe3O4/hydroxypropyl-β-cyclodextrin (3D-rGO/Fe3O4/HP-β-CD) by differential pulse voltammetry (DPV) approach.