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Preparation and Investigation of the Electrochemical Behavior of Sensors Modified with Reduced Graphene Oxide nanohybrids for Electrochemical Determinations of Some Biologically Important Compounds

Navabi, Mostafa | 2016

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 48701 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Shahrokhian, Saeed
  7. Abstract:
  8. In the first work, a stable composite film of silver nanoparticles decorated on reduced graphene oxide is easily prepared. The surface morphology of the modified electrode is characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. The electrochemical behavior of TNZ on the surface of the modified electrode is investigated by using linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). The prepared modified electrode acts as a highly sensitive platform for the voltammetric determination of tinidazole (TNZ). Voltammetric investigations demonstrated that, in comparison to the glassy carbon electrode individually coated with AgNPs, graphene oxide (GO) or rGO, a significant increase in the reduction peak current of TNZ is resulted on the surface of rGO-AgNPs composite modified electrode. The effects of experimental parameters such as the amount of the casted silver ion–GO mixture solution, the electro-reduction variables, the accumulation time and potential, the scan rate and pH of the buffered solutions on the electrochemical response of TNZ are examined. Under optimal conditions, the modified electrode showed a wide linear range for the reduction peak current of TNZ in the range of 0.01–10 μM with a detection limit of 3 nM. Finally, the prepared electrode is successfully applied for the determination of TNZ in pharmaceutical and clinical samples. In the second work, various carbon nanomaterials, including carbon nanotubes (CNTs), graphene oxide (GO), reduced graphene oxide (RGO) and rGO-CNT hybrids was used to modification of the surface of glassy carbon electrode .electrochemical behavior of raloxifene (RLX) was investigated by using linear sweep voltammetry (LSV). The results of voltammetric studies exhibited a significant increase in the anodic peak current of RLX on the surface of the electrode modified with rGO-CNT hybrid (2:1 ratio) film therefore rGO-CNT modified electrode was applied for the electrochemical determination of RLX. The surface morphology and nature of the rGO-CNT film was thoroughly characterized by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) techniques. Under the optimized experimental conditions, the modified electrode showed two linear dynamic ranges of 0.006–2.0 μM and 2.0–15.0 μM with a detection limit of 2 nM for the voltammetric determination of RLX. The modified electrode was successfully applied for the accurate determination of the trace amounts of RLX in pharmaceutical and clinical preparations
  9. Keywords:
  10. Cyclic Voltammetry ; Modified Electrodes ; Carbon Nanotubes ; Reduced Graphene Oxide ; Silver Nanoparticles ; Carbon Nanomaterials ; Tinidazole ; Raloxiphene

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