Electrochemical oxidation of adenine using platinum electrodes modified with carbon nanotubes

•Radio Frequency-catalytic Chemical Vapor Deposition was used for CNTs synthesis.•The electro-catalytic characteristics of the carbon nanotubes were tested.•MW and DW carbon nanotubes are more suitable for adenine electrochemical detection.

Single- (SWNTs), double- (DWNTs), and multi-walled (MWNTs) carbon nanotubes were synthesized by controlled Radio Frequency-catalytic Chemical Vapor Deposition (RF-cCVD). Their morphological and structural characteristics were identified using Transmission Electron Microscopy (TEM/HRTEM) and X-ray powder diffraction (XRD). Next, three platinum electrodes with identical amounts of each nanotube material (denoted Pt-SW, Pt-DW, and Pt-MW) were modified in order to test the electro-catalytic characteristics of the carbon nanotubes and further used for the electrochemical oxidation of adenine. The signal recorded with the Pt-SW electrode was very poor, due to the predominantly semiconducting properties of these nanotubes. In contrast, the signal recorded with Pt-DW or Pt-MW was well-defined, with the peak potentials at 1.07 and 1.01 V vs Ag/AgCl, respectively. In both cases, the detection limit (DL) for adenine was found to be 3×10−6 M.