Copper (II)-selective membrane electrodes based on Cu (II)-Schiff base complexes as an ionophore

A new PVC membrane electrode for copper (II) ion based on the mixture of mononuclear aqua-[N,N'-bis(salicylidene)-1,3,-propane-diaminato]copper (II) (I) and dinuclear dioxane-[N,N'-bis(salicylidene)-1,3-propane-diaminato]copper (II) dichloride (II) is developed. The electrode exhibits a Nernstian response for copper (II) ion over a wide concentration range, 1.0 x 10(-1) - 3.2 x 10(-5) M with a slope of 28.3 mV per decade. It has a relatively fast response time, 20 - 30 s, and can be used for at least four months without any considerable divergence in potential. The proposed electrode shows a high selectivity against Ca (II), Co (II), Zn (II), Ni (II), Mg (II), Sr (II). Ba (II), Cd (II), A] (III), Na (I), Hg (II) and Mn (II) and can be used in a pH range 4.5-6.5. Only Ag (I) ion was observed to have a significant interference. It is successfully used as an indicator electrode in potentiometric titration of copper (II) with EDTA and direct potentiometric determination of copper.