Nickel(II) Ion-Selective Electrode Based on 2,5-Thiophenyl bis(5-tert-Butyl-1,3-Benzoxazole

ABSTRACT A PVC membrane sensor for Nickel (II) ions based on 2,5-thiophenyl bis(5-tert-butyl-1,3-benzoxazole) as membrane carrier was prepared. The sensor exhibits a Nernstian response for Ni2+ ions over a wide concentration range (10−2–10−5M). It has a relatively fast response time and can be used for at least 2 months without any considerable divergence in potentials. The nature of the plasticizer, the additive, the concentration of internal solutions in the electrodes and the composition of the membrane were investigated. The proposed membrane electrode revealed very good selectivities for Ni2+ over a wide variety of other metal cations and could be used in pH range of 4.0–8.0. It was successfully applied for the direct determination of Ni2+ in solution and as an indicator electrode in potentiometric titration of nickel ion in both water and 85% acetonitrile solutions.