Highly Selective Iodide Poly(vinyl chloride) Membrane Electrode Based on a Nickel(II) Tetraazaannulene Macrocyclic Complex

Abstract

A PVC membrane electrode based on a nickel(II) tetraazaannulene macrocyclic complex as the carrier is described. The electrode exhibits an anti-Hofmeister selectivity sequence with a preference for iodide at pH 3.0–4.0. It has a linear response to iodide from 8.0 × 10^–6 to 1 × 10^–1 mol dm^–3 with a slope of –54.7 ± 0.2 mV per decade (20 °C), a satisfactory reproducibility and a rapid response time. The pH dependence of the potential response is discussed. The response mechanism of the electrode was investigated by ac impedance, quartz crystal microbalance and spectroscopic techniques. The electrode can be used for the determination of iodide in drug preparations.