An electrochemical Ni(II)-selective sensor-based on a newly synthesized dioxime derivative as a neutral ionophore

The suitability of a dioxime derivative, (2E, 3E)-2H-1,4-benzothiazine-2,3(4H)-dione dioxime as a neutral ionophore for the preparation of a PVC membrane electrode for Ni(II) ions was investigated. It can be used for at least 4 months without any considerable divergence in potentials and it has a relatively fast response of < 10 s. The prepared membrane exhibits a near Nernstian response for Ni2+ ions over a wide concentration range (1.0 x 10(-6) to 1.0 M) with a detection limit of 1.6 x 10(-6) M. At a working pH range of 2.0-6.5 the proposed membrane electrode revealed very good selectivity for Ni2+ ions over a wide variety of other cations. It was applied successfully as an indicator electrode in potentiometric titration of nickel ions with EDTA, and in the determination of Ni2+ in some water samples. (c) 2005 Elsevier B.V. All rights reserved.