Electrochemical detection dopamine by Ester-calix[n]arenes/graphene nanosheets modified electrodes

In this study, graphene nanosheets (GN) were modified by three ester-calix[n]arenes (ECnA, n = 4, 6, 8) using a simple self-assembly strategy. Three obtained ECnA/GN nanocomposites were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscope and electrochemical impedance spectroscopy, which confirmed that the various amount of ECnA molecules had been effectively loaded onto the surface of GN. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) measurements showed that the ECnA/GN modified electrodes exhibited high supramolecular recognition and enrichment capability and consequently displayed high electrochemical response toward dopamine (DA). At low concentration of guest molecule, the ECnA/GN modified electrodes show the better enrichment performances. Especially, EC8A/GN modified electrode exhibited an excellent electrochemical performance for DA with high current densities of 4.46 mA mmol− 1 L cm− 2, broad linear range (0.5 to 400 μM) and low detection limit (0.2 μM) at a signal-to-noise ratio of 3.