TiO2-graphene nanocomposite for electrochemical sensing of adenine and guanine

TiO₂-graphene nanocomposite was prepared by hydrolysis of titanium isopropoxide in colloidal suspension of graphene oxide and in situ hydrothermal treatment. It provides an efficient and facile approach to yield nanocomposite with TiO₂ nanoparticles uniformly embedded on graphene substrate. The electrochemical behavior of adenine and guanine at the TiO₂-graphene nanocomposite modified glassy carbon electrode was investigated. The results show that the incorporation of TiO₂ nanoparticles with graphene significantly improved the electrocatalytic activity and voltammetric response towards these species comparing with that at the graphene film. The TiO₂-graphene based electrochemical sensor exhibits wide linear range of 0.5–200 μM with detection limit of 0.10 and 0.15 μM for adenine and guanine detection, respectively. The excellent performance of this electrochemical sensor can be attributed to the high adsorptivity and conductivity of TiO₂-graphene nanocomposite, which provides an efficient microenvironment for electrochemical reaction of these purine bases.