Fabrication of a new electrochemical sensor based on gold nanoparticles decorated multiwall carbon nanotubes/graphene oxide nanocomposite for diclofenac determination

Diclofenac sodium (DS) is a synthetic nonsteroidal anti-inflammatory drug (NSAID), with analgesic and antipyretic effects. It is widely used to relieve post-operative pain and treatment of rheumatoid arthritis, osteoarthritis, non-articular rheumatism and musculoskeletal injuries [1,2]. It is also used in veterinary medicine for the treatment of food-producing animals [3]. Therefore, it is important to be able to determine the amounts of diclofenac in biological and pharmaceutical samples. In this study, a new electrochemical sensor was fabricated for determination of diclofenac sodium based on a gold electrode modified with functionalized multiwalled carbon nanotubes (f-MWCNTs)/graphen oxide (GO) nanocomposite and gold nanoparticles. A three-dimensional f-MWCNTs/GO hybrid composite was prepared by homogenous dispersion of f-MWCNTs and GO then the suspension of the composite easily drop cast at the surface of the gold electrode and the electrode was further modified with gold nanoparticles through electrochemical deposition. Electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), scanning electron microscopy (SEM) and energy dispersion spectroscopy (EDS) were used to investigate the surface of the modified electrode. Several parameters such as PH, scanning rate and the amount of nanocomposite controlling the performance of the sensor were examined and optimized. The proposed electrochemical sensor exhibited high specific electrochemical response to diclofenac and it was used for voltammetric determination of diclofenac in real sample solutions with promising results.