Voltammetric Determination of Isoniazid using Cyclic Renewable Mercury Film Silver Based Electrode

Abstract

A new cathodic voltammetry method for the determination of isoniazid based on the cyclic renewable mercury film silver based electrode (Hg (Ag) FE) is presented. The effects of various factors such as: preconcentration potential and time, pulse height, step potential and supporting electrolyte composition are optimized. The calibration graph is linear from 5 nM up to 500 nM (68.55 µgL -1 ). For Hg (Ag) FE with a surface area of 9.7 mm 2 without time consuming preconcentration the limits of detection LOD and quantification LOQ were 4.1 nM and 10.5 nM of isoniazid, respectively. The repeatability of the method at a concentration level of the analyte as low as 0.5 nM, expressed as RSD is 3.6% (n=6). The proposed method was successfully applied in analysis of isonizid in simple and composed pharmaceutical formulations.