Surface Morphology Analysis of Graphene Transfer on SiO2 with BPA Aptasensor Detection using Electrochemical Impedance Spectroscopy

Abstract

Bisphenol A or BPA is one of the highest produced chemicals in the world. The production of polycarbonate plastic and epoxy resin are used to make variety of consumer goods and it is frequently employed BPA as a raw material. BPA is one of the endocrine disruptors which is related to a wide range of adverse health effects that can cause reproductive disorders and many kinds of cancers. In the work, the novelty of electrochemical sensor of BPA was constructed on a raphene modified electrode using graphene transfer method. In this work, High-power microscope and scanning electron microscopy were used to study the production and characterization of the graphene, with two significant mapping graphene at 20% and 80%. The existence of graphene on silicon oxide was analyzed using Raman Spectroscopy while the composition of the materials was analyze using Fourier-Transform Infrared Spectroscopy. In this analysis, both analysis data from Raman and FTIR clearly shown that 80% mapping graphene is the best option which resulting to the high surface coverage. The electrochemical performance of the mapping 80% graphene electrode was examined using Electrochemical Impedance Spectra. The increase in charge transfer resistance (Rct) both before and after the addition of BPA denotes the development of the charge at the electrode surface. The equivalent circuit shows the Rct of graphene increased from 0.4 k Ω to 1.2 k Ω and drastically increased to 300 kΩ when the device was introduced with BPA due to the existence of a negative charge carrier and the repelling contact.