Ionic liquid based electrochemical sensor for the detection of efavirenz

Abstract

This study reports an electrochemical carbon sensor modified with graphene oxide (GO), silver nanoparticles (AgNPs) and 1-Allyl-3- methylimidazolium dicyanamide (AmmDCA) ionic liquid. The ionic liquid-based electrochemical sensor has been developed for the detection of efavirenz (EFV), a drug used in the fixed dose combination tablet for the treatment of HIV. The AgNPs/GO/AmmDCA nanocomposites were characterized via scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infra-red (FT-IR) spectrometer, and Ultraviolet–visible (UV–Vis) spectroscopy. The GCE/GO/AgNps/AmmDCA sensor demonstrated good electrocatalytic activity towards the detection of efavirenz, using the supporting electrolyte, phosphate buffer at pH 10.0 and accumulation time of 30 s, within the linear dynamic range of 1.0 to 7.0 µM with a detection limit of 0.0474 nM and limit of quantification 0.158 nM. The surface area of the ionic liquid modified electrode was 0.421 cm2 calculated using the Randles-Sevcik equation which was four times higher than the glassy carbon electrode. The developed sensor in this study displayed an increase in electrochemical signal of EFV, ≥800 µA, and the calculated recoveries were in the range of 98.5 – 103%, proving the high sensitivity, good selectivity and stability of the developed sensor thus proven to be valuable in pharmaceutical samples analysis.