Tricoordinate Schiff base copper(II) complex as neutral carrier for highly selective thiocyanate electrode

A new solvent polymeric membrane electrode based on a tricoordinate Schiff base copper(II) complex as neutral carrier is described, that demonstrates excellent selectivity to thiocyanate relative to many common anions and over a wide linear range of 2.6 x 10(-6) -1.0 x 10(-1) M with a detection limit of 8.0 x 10(-7) M and a near-Nernstian slope of -57.6mV/decade in pH 4.0 of phosphate buffer solution at 25 degrees C. The electrode displays an anti-Hofmeister selectivity sequence in the following order: SCN- > Sal(-) > ClO4- > I- > NO2- > Br- > NO3- > Cl- > SO32- > SO42- > H2PO4-. The response mechanism is discussed in view of the AC impedance technique and the ultraviolet (UV) spectroscopy technique. The electrode was successfully applied to the determination of thiocyanate ion in wastewater and human saliva.