A Novel Graphene/Chitosan/ZrO2 Nanocomposite Sensor for Electrochemical Investigation of a Non-Steroidal Anti-Inflammatory Drug Tolfenamic Acid

A highly sensitive and selective sensor based on graphene/chitosan/zirconium oxide nanocomposite modified GCE (GRP/CHIT/ZrO₂/GCE) has been fabricated for a convenient study of anodic behavior of tolfenamic acid (TA) using cyclic voltammetry (CV) and square wave voltammetry (SWV). Scanning electron microscopy (SEM) was used to investigate the assemble process of the nanocomposite modifier (GRP/CHIT/ZrO₂). Electrochemical characterization of the modified electrode has been characterized by CV and electrochemical impedance spectroscopy. GRP/CHIT/ZrO₂/GCE exhibited higher electrocatalytic behavior towards the electro-oxidation of TA as compared to GRP/CHIT/GCE and bare GCE which can be described on the basis of mass transport regime within the porous layer of the nanocomposite modifier. TA exhibited an irreversible diffusion controlled process and a linear dynamic range from 5-40 ng/mL at GRP/CHIT/ZrO₂/GCE. The proposed method has been further scrutinized by the successful determination of TA in pharmaceutical formulation.