Voltammetric and Amperometric Determination of Iodate using Ionic Liquid/Polyoxotungstate/MWCNTs-COOH Organic-Inorganic Nanohybrid Modified Glassy Carbon Electrode

In this study, a nanohybrid modified glassy carbon electrode (GCE) was successfully fabricated with a tri-component nanocomposite consisting of (۱,۱'-(۱,۴-Butanediyl) dipyridinium) ionic liquid (bdpy), PW۱۱O۳۹Co(H۲O) (PW۱۱Co) polyoxometalate (POM), and carboxyl functionalized multi-walled Carbon Nanotubes (MWCNTs-COOH) by drop-casting, followed by electrodeposition technique. The morphological, electrochemical, and electrocatalytic properties of the (bdpy)PW۱۱Co/MWCNTs-COOH/GCE were investigated by field emission scanning electron microscopy (FE-SEM) combined with energy-dispersive X-ray spectroscopy, voltammetry, and amperometry methods. The FE-SEM images well showed immobilization of (bdpy)PW۱۱Co/MWCNTs-COOH on GCE through deformation of the mirror surface to the rough surface. The electrochemical test results confirmed that modified electrode has high stability and remarkable electrocatalytic behavior toward the reduction of iodate ion. The proposed sensor displayed two linear ranges of ۱۰.۰-۲۰۰.۰, and ۲۰۰.۰-۱۶۰۰.۰ µmol L-۱ with LOD of ۲۷.۶×۱۰-۲ µmol L-۱ (S/N=۳), and sensitivity of ۴۱.۰ µA mmol L-۱, and ۲۰.۰ µA mmol L-۱, respectively, by amperometry method. Moreover, the results of the electrochemical experiments indicated that this sensor has excellent selectivity, good reproducibility, repeatability, and analytical performance in real samples.