Electrocatalytic Oxidation and Flow Injection Analysis of Isoniazid Drug Using an Unmodified Screen Printed Carbon Electrode in Neutral pH

Manavalan Gopinathan; Natarajan Thiyagarajan; Murugan Thiruppathi; Jyh‐Myng Zen

Index: 10.1002/elan.201800021

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Abstract

In this work we report electrocatalytic oxidation and flow injection analysis of tuberculostatic drug isoniazid (INZ) based on a disposable and unmodified screen printed carbon electrode (SPCE). Instead of using chemically modified electrode to increase the sensitivity at low overpotential, the same purpose can be achieved simply by preanodization of a bare SPCE in a suitable electrolyte medium. Surface characterization of the as‐preanodized electrode by X‐ray photoelectron spectroscopy and Raman spectroscopy indicate that both oxygen functionalities and edge/defect sites effectively assist the INZ oxidation. Flow injection analysis extends its applicability with a wide linear range up to 1 mM and an enhanced sensitivity of 100 nA μM−1 with a low detection limit of 2.7 nM (S/N=3). These good analytical features accomplished with disposable and economical devices could make possible the implementation of this methodology for INZ on‐line monitoring in pharmaceuticals.