Square Wave Voltammetric Determination of 8-Hydroxyquinoline-2-Carboxaldehyde Isonicotinoyl Hydrazone (INHHQ), a Promising Metal-Protein Attenuating Compound for the Treatment of Alzheimer’s Disease, Using a Multiwalled Carbon Nanotube (MWCNT) Modified Glassy Carbon Electrode (GCE)

An analytical method for the determination of 8-hydroxyquinoline-2-carboxaldehyde isonicotinoyl hydrazone (INHHQ) is reported for the first time. The electrochemical method involving INHHQ was performed at a glassy carbon (GC) electrode modified with multiwalled carbon nanotubes (MWCNTs). The GC-MWCNTs promoted a significantly large enhancement in the Faradaic current employing square wave voltammetry (SWV) to determine INHHQ in the fortified extracts of the brain from Wistar rats. In addition, the MWCNTs increased the active electrode area, produced an electro-catalytic effect and provided significantly faster electron transfer. The quantification of INHHQ was made by the use of a supporting electrolyte consisting of Britton-Robinson (BR) buffer at a concentration of 0.02 mol L−1 and a pH of 11.0 in 0.25 mol L−1 KCl. The quantitative assay using square wave voltammetry was achieved by the serial addition of a standard into the electrochemical cell containing the sample. The limit of detection (LOD) for the protocol was equal to 0.25 µg mL−1 (0.85 µmol L−1). A procedure involving thin-layer chromatography (TLC) was employed in order to improve the selectivity required to determine INHHQ. The recoveries of the analyte in brain tissue from Wistar rats were statistically comparable to the values obtained by a high-performance liquid chromatography (HPLC) protocol.