Plasticizer-free Hydrazonic Dibenzo-18-crown-6 derived lead ion sensing electrodes

Abstract

The redox behaviours of three dibenzo-18-crown-6 hydrazones were investigated via cyclic and square wave voltammetries, prior to their electropolymerization onto a platinum working electrode to yield three novel Ion Selective Electrodes (ISEs) whose lead sensing behaviours were investigated via Differential Pulse Anodic Stripping Voltammetry (DPASV) and Electrochemical Impedance Spectroscopy (EIS), subsequent to their characterization via Scanning Electron Microscopy (SEM). For all three ISEs, the electrosynthesized polymeric Ion Selective Membranes (ISM) are multi-layered with pores of diverse dimensions; a feature which allows wide linear ranges (4–107 ppm) in all cases, relative to Flame Atomic Absorption Spectroscopy (FAAS); one of the traditional “go-to” methods for metal ion quantification. Additionally, these ISEs allow selective detection of Pb²⁺ at concentrations below 20 ppm even in the presence of high concentrations of competing metal ions, except when excess Al³⁺ is present. Overall, given the relative ease of modification and low cost of these hydrazonic dibenzo-18-crown-6 ISEs, coupled with their performance, they represent a viable starting point for the development of high quality, low cost lead ISEs.