Performance Improvement of Working Electrode Using Grafted Polymer Modified with SiO₂ Nanoparticles

A new modified glassy carbon electrode (GCE) with grafted polymer (GP)/SiO₂ nanoparticles (SiO₂ NPs) were prepared using mechanical attachment method to produce a new sensor in cyclic voltammetric technique. The new working electrode GP/SiO₂ NPs/GCE was characterized by a standard solution of 1 mM K₄[Fe(CN)₆] with 1 M K₂HPO₄ as an electrolyte to study the redox current peaks of FeⅡ/FeⅢ ions at different concentrations such as scan rate, pH, determination of diffusion coefficient (D_f), reliability and stability of the modified GCE. It was found that the new modified electrode enhanced the redox current peaks of FeⅡ/FeⅢ from 12 μA to 20 μA and -5 μA to -15 μA for oxidation and reduction peaks in GCE, repectevely. So, the current ratio (Ipa/Ipc) for the new modified electrode was 1, and the potential peak separation (ΔEpa-c) was 100 mV, which indicated good electrochemical properties as an irreversible electrode and heterogeneous reaction. Good reliability and stability of modified GCE was obseved with low detection limit. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) analysis of the nano-deposit was also studied.