Electrochemical sensor-based gold nanoparticle/poly(aniline-co-o-toluidine)/graphene oxide nanocomposite modified electrode for hexavalent chromium detection: a real test sample

Abstract

ABSTRACTThis paper presents the fabrication of poly(aniline-co-o-toluidine)/graphene oxide nanocomposite with a general abbreviation [PANI-co-PoT/GOa–e] by well-known in-situ oxidative polymerization method with ultrasonic assistance. These materials were based on variable loading of GO when prepared. The chemical structures of the composite materials were confirmed by characterization technique. The FE-SEM and TEM micrographs were used to investigate the morphological features. Furthermore, FT-IR, XRD, TGA, and electrical conductivity measurements were utilized to estimate its complete performance. All nanocomposites showed CDTmax values in the range of 287.25–463.51 ºC which is significantly higher than that observed for pure copolymer (204.79 ºC). The main focus of this paper is to study the electroselective application using gold nanoparticle as a coating. A steady electroactive modified electrode [AuNPs/PANI-co-PoT/GO] was effectively prepared on a gold electrode (Au) surface using an electroadsorption process for the determination of Cr(VI). The electrochemical attitude of the modified sensor toward the reduction of Cr(VI) was studied by a square wave voltammetry (SWV) and a cyclic voltammetry (CV) technique. The AuNPs/PANI-co-PoT/GO modified electrode displayed a perfect electrochemical activity toward the reduction of Cr(VI). Using an SWV method, the modified electrode gave a linear response to Cr(VI) through the concentration range 5–500 µM with a limit of detection 0.0215 µM. The suggested sensor displayed good stability, sensitivity and selectivity and has exhibited potential for the detection of Cr(VI) in real samples.