Preparation and Investigation of the Electrochemical Behavior of Sensors Based on Glassy Carbon Electrode Modified with Various Carbon Nanostructures Decorated by Some of Metal Nanoparticlesfor Determination of Ceftizoxime

Ranjbar, Saba | 2015

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 47441 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Shahrokhian, Saeed; Masoumeh Ghalkhani
  7. Abstract:
  8. In the recent years, sensors and biosensors attracts much attentions as a suitable devices in analytical chemistry. In this meantime carbon nanostructures and metal nanoparticles act as a good choice owing to their unique properties such as high electrical conductivity andmechanical and chemical stability in modification of the surface of sensors and biosensors. Because of importance of analysis the trace amounts of pharmaceutical and biological compounds, in this studies the surface of glassy carbon electrode was modified with some carbon nanostructures and metal nanoparticles for electrochemical investigation and determination of pharmaceutical and clinical compounds.In the first work, a modified glassy carbon electrode with a film of nanodiamond–graphite nanomixture decorated with Ag nanoparticles was constructed and used for sensitive voltammetric determination of ceftizoxime (CFX). Then, the prepared nanocomposite was characterized by electron microscopy, spectroscopy and electrochemical techniques. With modification of the surface of the glassy carbon electrode by modifier and optimization of the experimental parameters such as deposited amount of the modifier suspension, pH of the supporting electrolyte and accumulation potential and time, significant voltammetric response was observed for oxidation of CFX compared to unmodified electrode, These results illustrate that the modified electrode increased the effective surface area and exhibited an excellent catalytic effect in the electro-oxidation of CFX. Under the optimum conditions, the modified electrode showed a linear response to the concentration of CFX in the range of 0.02–7 µM with a detection limit of 6 nM. The prepared modified electrode has some remarkable electrochemical properties such as simple preparation, high sensitivity, excellent repeatability, reproducibility and long–term stability and used for determinations in pharmaceutical and clinical samples.
    In the second work, the surface of the glassy carbon electrode was coated with thin films of five carbon nanostructures to comparison of sensitivity, stability and repeatability toward CFX responses. MWCNTs selected as a carbon nanostructure that created these parameters. Then with attention to properties of the metal nanoparticles and functional groups in the surface of CFX, five metal nanoparticles electrochemically deposited on the surface of the MWCNTs/GCE. The resulting nanoparticles were characterized by the cyclic voltammetry. Finally, with attention to parameters such as remarkable increase in analytical signals, sensitivity, stability and repeatability toward CFX response, AuNPs/MWCNTs/GCE chose as a promising candidate for the trace analysis of CFX in pharmaceutical and clinical preparations. Experimentally parameters (accumulation time and potential deposition, film thickness of the modifier, pH of the supporting electrolyte) and electro-deposition conditions of Au nanoparticles (time and potential deposition and salt concentration of Au) were optimized and under these conditions, linear response for CFX in the range of 0.02-8 µM with detection limit of 6nM was obtained. The modified electrode was successfully applied for the accurate determination of trace amounts of CFX in pharmaceutical and clinical preparations. Also, in the presence of some potentially interference, this modified electrode was tasted and suitable results was achieved
  9. Keywords:
  10. Glassy Carbon Electrode ; Carbon Nanostructures ; Metallic Nanoparticles ; Voltammetric Measurement ; Ceftizoxime ; Electrochemical Investigation

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