Electrochemical determination of nanomolar levels of isoniazid in pharmaceutical formulation using silver nanoparticles decorated copolymer

Abstract

A copolymer of methyl methacrylate and 2-acrylamido-2-methylpropane sulfonic acid (P(MMA-co-AMPS)) and silver nanoparticles (Ag NPs) incorporated P(MMA-co-AMPS) (Ag-P(MMA-co-AMPS)) are used to construct efficient electrochemical sensing platforms (ESPs) to quantitatively determine isoniazid (INZ) at neutral pH conditions. Cyclic voltammetry, amperometry and electrochemical impedance spectroscopy are used as diagnostic tools for INZ determination at these ESPs in pH 7.0 phosphate buffer solution. It has been found that P(MMA-co-AMPS) copolymer facilitates the INZ oxidation with improved electrochemical behaviors. At Ag-P(MMA-co-AMPS), electrochemical characteristics of INZ is much improved than at P(MMA-co-AMPS) due to the interaction of INZ with Ag NPs. Based on the linear increase in oxidation current, a sensitive INZ electrochemical sensor is constructed. The sensor displays a linear calibration range from 50.0 nM to 150.0 μM for INZ determination. Detection limit (based on three times standard deviation of the blank) and sensitivity of this sensor is 10.0 nM and 197 nA μM-1 cm-2, respectively. Further, P(MMA-co-AMPS) and Ag-P(MMA-co-AMPS) materials are successfully applied for analysis of INZ in presence of other biologically important molecules and also in a pharmaceutical formulation. The obtained results are very much consistent with the INZ amount originally present in the pharmaceutical formulation. © 2015 Elsevier Ltd. All rights reserved.