In this study, we synthesized graphene oxide (GO) at different oxidation times (30, 60 and 120 min) using a modified Hummer's method and investigated their carbon-to-oxygen (C/O) ratios, the % C-C double bond, the diffraction pattern, their topography and their electrochemical behaviour both by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). All GOs synthesized were compared with a GO from commercial source. Graphite-epoxy composite (GEC) electrodes fabricated in our laboratory were modified with GO and electrochemically reduced graphene oxide (ERGO) in preliminary assays to elucidate its applicability for enhanced DNA aptamer biosensing applications. (C) 2017 Elsevier Ltd. All rights reserved.