A glassy carbon electrode modified with amino-functionalized graphene oxide and molecularly imprinted polymer for electrochemical sensing of bisphenol A

Abstract

The main aim of the work was to develop an efficient strategy for preparing molecularly imprinted polymers (MIPs) on the surface of graphene oxide (GO) sheets. Amine functionalization of GO was accomplished by a facile and efficient procedure with 3-aminopropyltriethoxysilane (APTES). Then, the template was immobilized onto amino-functionalized GO in order to improve the recognition ability of MIP-based sensors. Also, prior to polymerization, ethylene glycol dimethacrylate was grafted onto the APTES coated graphene oxide sheets by the Michael addition reaction. In this way, many homogeneous imprinting sites were formed on the GO sheets. The resulting composite was placed on a glassy carbon electrode (GCE) which then was used for determination of bisphenol A (BPA) by electrochemical technique. The composite of amino-functionalized GO and MIP (GO/APTES–MIP) was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy and energy dispersive X-ray spectroscopy. The electrochemical behaviors of the sensors were investigated by cyclic voltammetry and differential pulse voltammetry (DPV) techniques. Compared with non-imprinted polymer, the DPV current response of MIP sensor is about 4.6 times larger. Under the optimized conditions, GO/APTES–MIP sensor displays two linear ranges (from 0.006 to 0.1 μM and 0.2 to 20 μM) for determination of BPA, and the detection limit is 0.003 μM (at an S/N ratio of 3). The MIP-based sensor was applied to the in-situ determination of BPA in milk and mineralised water without any pre-treatment and matrix interfering effects.