Nickel(II)-selective membrane potentiometric sensor using a recently synthesized Schiff base as neutral carrier

A new PVC membrane electrode that is highly selective to Ni(II) ions was prepared by using N,N′-bis-(4-dimethylamino-benzylidene)-benzene-1,2-diamine as a suitable neutral carrier. The sensor exhibits a Nernstian response for nickel ions over a wide concentration range (1.0×10−2 to 2.0×10−7 M) with a slope of 30±1 mV per decade. It has a response time of <10 s and can be used for at least 2 months without any measurable divergence in potential. The electrode can be used in the pH range from 4.5 to 9.0. The proposed sensor shows fairly a good discriminating ability towards Ni2+ ion in comparison to some hard and soft metals. The electrode was used in the direct determination of Ni2+ in aqueous solution and as an indicator electrode in potentiometric titration of nickel ions.