Electrocatalytic Behavior of TiO2/MWCNTs Nanocomposite Decorated on Glassy Carbon Electrode for Individual and Simultaneous Voltammetric Determination of Adenine and Guanine in Real Samples

An electrochemical sensor based on titanium dioxide (TiO 2 ) and multi-walled carbon (MWCNTs) nanocomposite was fabricated to simultaneous detection of guanine (GU) and Adenine (AD). Nanocomposite was dispersed in water/ethanol with a certain aspect ratio and drop cast onto a glassy carbon electrode. FT-IR, scanning electron microscopy (SEM) and EDX methods as well as electrochemical technique, such as cyclic voltammetry (CV), linear sweep voltammetry (LSV) and differential pulse voltammetry (DPV) were performed to characterize the TiO 2 −MWCNTs nanocomposite and describe the electrochemical oxidation process. Fabricated sensor shows separate and well-defined peaks for AD and GU, by which one can determine these purine bases individually or simultaneously. Response to GU and AD are linear in the 2.84 to 125 μ M concentration range, and the detection limits are 0.97 and 0.4 μ M for GU and AD, respectively. The sensor was successfully utilized for the measurement of GU and AD in a diluted human serum sample. The fabricated sensor exhibited high sensitivity, good reproducibility, long-term stability and could be used to quantify of GU and AD in real samples sample successfully