PREPARATION OF POLYMER CARBON-NANOTUBE BASED COMPOSIDE ELECTRODES AND APPLICATION TO DETERMINATION OF SEROTONIN
Project no. 588 · Status: Kapanmış · 2014
Summary
In this thesis study, highly active multi-walled carbon nanotube and/or polyaniline based composite structures were fabricated onto glassy carbon electrode surfaces and then the morphological, chemical and electrical properties of these electrodes surface were characterized. The prepared composite electrodes were used to examine the electrochemical behavior of serotonin at different pHs. When peak currents and peak potentials of serotonin on bare and composite electrodes were compared for different pH’s of sopperting electrolyte, the optimum working pH was obtained as 7.4 by using phosphate buffer solution. On the other hand, the best electrocatalytic activity toward serotonin was obtained with multiwalled-polyaniline nanotube composite electrode (MWCNT-PANI/GCE) in pH 7.4 phosphate buffer solution. The formation of polyaniline on the GCE with cyclic voltammetry was optimized by varying aniline monomer concentration and the cycle number. After the optimization of experimental conditions, The differential pulse voltammetry studies were performed for sensitive and selective determination of serotonin with all electrodes. The fabricated MWCNT/PANI/GC composite electrode showed best electrochemical activity for serotonin oxidation at optimum conditions. A wide linear calibration curve was obtained within the concentration range between 1x10-7 to 1.2x10-5 mol L-1 pH 7.4 phosphate buffer solution with the limit of detection 3.33x10-8 mol L-1 (S/N=3) with MWCNT/PANI/GCE. The composite electrodes surface morfology, chemistry and electrcity were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy(XPS) and electrochemical impedance spectroscopy(EIS). The morphologies of the prepared composite electrodes were investigated by using scanning electron microscopy, where the chemical composition and the electrical properties of the electrode surfaces were examined with X-ray photoelectron spectroscopy and electrochemical impedance spectroscopy respectively.