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Abstract: Sub-10nm CeO2 nanoparticles decorated multi-walled carbon nanotubes has been constructed for electrochemial determination of guanine and adenine. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) were used to characterize the nanoparticles CeO2/MWCNTs. Electrochemical impedance spectroscopy (EIS) was used to characterize the electrode modifying process. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to study the electrocatalytic activity toward the electrochemical oxidation of guanine and adenine. The detection limit (S/N=3) for adenine and guanine was found to be 20 and 10nM, respectively. The obtained sensitivity toward guanine and adenine was 1.26 and 1.13μA/μM in the linear concentration range 5–50μM and 5–35μM, respectively. These results demonstrate that the carbon nanotubes could provide huge locations and facilitate the adsorptive accumulation of the guanine and adenine, and the CeO2 nanoparticles are promising substrates for the development of high-performance electrocatalysts for biosensing. [Copyright &y& Elsevier]

Abstract: The fabrication of Nano-Au/Porous-TiO2 composite modified glassy carbon electrode (GCE) and its application in the determination of hydrazine were proposed. The morphological characterization was examined by transmission electron microscope and scanning electron microscopy. The Nano-Au/Porous-TiO2/GCE exhibited a wide linear range of hydrazine from 2.5 to 500μM, with a detection limit of 0.5μM at a signal-to-noise ratio of 3 and with a fast response time (within 3s). Furthermore, the reaction mechanism of the hydrazine on the Nano-Au/Porous-TiO2/GCE was explored. The ease of fabrication, high stability, and low cost of the modified electrode are the promising features of the proposed sensor. [Copyright &y& Elsevier]