Fabrication of Zn(II) Selective Polyvinyl Chloride Membrane Electrode based on N,N'-bis(1-hydroxynaphthalene-2-carbaldehyde)-o-phenylenediamine as an Ionophore: Experimental and Theoretical Approaches

Abstract

A new ion-selective polyvinyl chloride membrane electrode based on Schiff base [N,N′-bis(1-hydroxynaphthalene-2-carbaldehyde)-o-phenylenediamine] as an ionophore is successfully worked out as sensor for Zn(II) ions. The electrode shows excellent potentiometric response characteristics and displays a linear emf versus log[Zn²⁺] response over a wide concentration range of 1.0 × 10^–7‒0.1 M with nernstian slope of 29.0 ± 0.1 mV/decade with the detection limit of 1.8 × 10^–8 M. The sensor exhibits the advantages of fast response time (<10 s). The lifetime of the sensor is about 3 months. It was used as an indicator electrode in the potentiometric titration of Zn(II) with EDTA and for the determination of Zn(II) in pharma samples. The results were validated by using quantum mechanical density functional theoretical calculations. Theoretical studies proved prominent affinity of ligand towards Zn(II) ion.