Highly Selective Thiocyanate Electrode Based on Bis‐bebzion Schiff Base Binuclear Copper(II) Complex as Neutral Carrier

Abstract

A highly selective polyvinyl chloride (PVC) membrane electrode, based on N,N′‐(aminoethyl)ethylenediamide bis(2‐benzoideneimine) binuclear copper(II) complex [Cu(II)‐AEBB] as neutral carrier, was prepared for thiocyanate (SCN−) determination, which displays an anti‐Hofmeister selectivity sequence for a series of anions in the following order: SCN−>ClO4 −>Sal− > I−>NO3 −>Br−> Cl−>NO2 −>SO3 2−>F−>H2PO4 −>SO4 2−. The electrode exhibited near‐Nernst response for SCN− with a slope of –59.0 mV/decade over a wide concentration range (8.5×10−7∼6.8×10−1 mol/L) with a detection limit of –5.0×10−7 mol/L in pH 5.0 phosphate buffer solution at 25°C. Alternating current (AC) impedance and equivalent circuits were used to investigate the thiocyanate response mechanism of the membrane doped with [Cu(II)‐AEBB].