Electrochemical behaviour and sensing of chlorpromazine at polymer-free kaolin-based nanosodalite and nanosodalite-graphene foam film modified glassy carbon electrodes

Abstract

A nanosodalite (SOD) was synthesized utilizing Cameroonian kaolin and then used to prepare a nanocomposite (SOD-GF) with graphene foam (GF). The as-synthesized materials were characterized using X-ray diffractometry (XRD), Fourier transform-infrared (FT-IR) spectroscopy, N2 adsorption-desorption and scanning electron microscopy coupled with emission dispersive X-ray (SEM/EDX). The results show a pure sodalite with high degree of crystallinity with crystallite size and BET surface area of 38.3 nm and 22 m2 /g, respectively. The composite’s characterization revealed a well-integrated material in which the structural integrity of each material is maintained, its surface area being 4-fold that of pristine SOD. Stable SOD and SOD-GF modified glassy carbon electrode (GCE) were prepared by drop coating without a binder and utilized to study the electrochemistry of chlorpromazine (CPZ) in acidic, neutral and basic pHs. It appeared that (i) CPZ’s electrochemical oxidation was a two-step one-electron process at SOD/GCE and a one step two-electron process at SOD-GF/GCE and (ii) the electrochemical reaction mechanism was an EEC mechanism at SOD/ GCE while at SOD-GF/GCE the mechanism was EEC at pH<4 and EC for greater pH. SOD/GCE and SOD-GF/GCE were used to sense CPZ within CPZ’s concentration ranging from 0.5-30 μM with low detection limits.