Electrochemical Current Amplification of Bisphenol A in the Presence of Magnetite Nanoparticles

Electrodes that were dropcast with a combination of magnetite (Fe₃O₄) nanoparticles (FeNPs), COOH-functionalized multiwalled carbon nanotubes (f-MWCNTs), and polyvinylpyrrolidone (PVP) showed large enhancements of anodic current signals (2500% increase on average) when performing cyclic voltammetry (CV) analysis of bisphenol A (BPA). The f-MWCNT/FeNP/PVP composite was characterized by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis, and transition electron microscopy (TEM). It was observed that the high degree of current amplification is selective only toward BPA and not for other polyphenol compounds. Nevertheless, substantial variability in oxidative peak currents across experiments hinders reliable analytical applications. Fe₃O₄ nanoparticles were chosen because of their unique electronic properties where ‘electron hopping’ can occur between Fe²⁺ and Fe³⁺ ions. This renders magnetite particles highly conductive and possesses potential electrochemical reducing properties. The results were interpreted as a reductive recycling of BPA on the surface of the modified electrode via Fe²⁺, which continuously regenerates BPA molecules from its oxidized form, thereby causing an accumulation of electroactive species leading to enhanced current.