Thesis (Ph.D.) - Cairo University - Faculty of Science - Department of Physical Chemistry

Novel promising electrochemical Caffeine (Caf) sensors were achieved through various ways. Firstly by chemical mixing of Co (II, III) Oxide Nanoparticles on a carbon paste electrode (CPE), secondly by chemical mixing of graphene oxide (GO) nanoparticles and reduced glutathione (GSH) with CP, thirdly by mixing multiwalled carbon nanotubes (MWCNT) and zeolite (Zeo) with CP and/or finally electrodeposition of Ag- nanoparticles on cellulose acetate phthalate (CAP) and chitosan (Chit) polymers with CP. Electrochemical techniques including cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), Chronoamperometry (CA) and differential pulse voltammetry (DPV) were used in the present investigation in addition to analysis techniques like Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), Energy Dispersive X-Ray (EDX) and X-Ray Diffraction (XRD) techniques, in both aqueous and surfactant modified media using sodium dodecyl sulphate (SDS). Caf measurements were investigated in various supporting solutions of pH range (0.75-5.00) containing 0.5 mmol L-1 of SDS. Acceptable results were attained for the finding of Caf in real samples as beverages and drug samples

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