Construction and characterization of GCE/MWCNT/Au-NP as a new impedimetric and voltammetric sensor for determination of gemfibrozil in pharmaceutical and biological samples

Abstract

A novel electrochemical sensor was constructed for the impedimetric and voltammetric determination of gemfibrozil (GEM) by modification of the glassy carbon electrode (GCE) using multi-walled carbon nanotubes (MWCNTs) and gold nanoparticles (Au-NPs). The inherent properties of MWCNTs such as their high surface area and high conductivity, and the capability of fast electron transfer of Au-NPs were taken into account in constructing the sensor. Scanning electron microscopy (SEM), energy dispersive x-ray (EDX), and electrochemical impedance spectroscopy (EIS) were used for the characterization of the MWCNTs/Au-NPs modified GCE (GCE/MWCNT/Au-NP) surface. The redox behavior of GEM on the surface of GCE/MWCNT/Au-NP was studied by voltammetric techniques. After optimizing the effective experimental parameters, the sensor’s response toward increasing GEM concentration was studied by square wave voltammetry (SWV) and EIS. The results obtained showed linear responses in the GEM concentration ranges of 0.15–45.0 and 0.10–45.0 μmol L−1 for SWV and EIS, respectively. The experimental 3σ detection limits were 0.10 and 0.074 μmol L−1 for SWV and EIS, respectively. The repeatability of 1.07% and reproducibility of 5% were achieved for five replicate determinations of 15.0 μmol L−1 of GEM. The sensor efficiency was investigated by its application in the analysis of the real samples pharmaceutical and spiked human serum, and the results obtained were satisfactory.