Prerequisites for Development of Electrochemical Planar Sensor Based on RGO–PPD–SiW Composite for Determining Isoniazid Content in Biological Liquids

Abstract

A new redox-active composite material based on reduced graphene oxide (RGO), poly-o-phenylenediamine (PPD), and silicotungstic acid (SiW) is studied. The SEM data showed an abrupt decrease in the content of oxygen atoms in the composite as compared to pure graphene oxide (GO). This is associated with its reduction to RGO in the course of RGO–PPD–SiW synthesis. A combination of RGO conductivity and redox catalysis due to the electroactive components (PPD and SiW) enables one to develop various sensors by applying RGO–PPD–SiW onto planar electrodes (screen-printed carbon electrodes, SPCE). In this work, the possibility of developing a sensor for the content of antituberculous antibiotic isoniazid (isonicotinic acid hydrazide C6H7N3O, INAH) is studied. Using the CVA method, it is shown that the concentration dependence of isoniazid oxidation current is linear. The electrocatalytic behavior of the composite during the isoniazid oxidation is also supported by the impedance spectroscopy.