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-beta-cyclodextrin (HP-beta-CD) to construct a novel nanocomposite (3D-rGO/Fe3O4/HP-beta-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-beta-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 mu M, 0.02 - 25 mu M and 10 - 350 mu M; (c) detection limits of 3.3 nM, 6.7 nM and 3.3 mu M (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%.