Carrier-Based Nickel (II) Selective Electrode Using 2,2´-Ditho(Bis)Benzothiazole as a Ionophore

Abstract: Potentiometric methods compared to the other common analytical methods have considerable advantages such as their simplicity of preparation and ease of application, fast response time, low cost, wide dynamic range with significant low detection limit [1, 2]. The present work deals with developing a novel high selective membrane electrode based on 2,2´-Ditho(bis)benzothiazole for accurate determination of trace amount of nickel (II). The amounts of ionophore (5 mg), PVC(30 mg), dioctyl phthalate (DOP) as a plasticizer (63.5 mg) and sodium tetra phenyl borate (NaTPB) as an ionic additive (1.5 mg) were optimized in the preparation of the membrane. The effects of various parameters such as pH, different cation interferences such as Cu2+, Mn2+،Cd2+ ،Sr2+ ،Al3+ ،Cr3+ ،Ca2+ ،Zn2+ ،Co2+ ،Pb2+ ،Ba2+ ،NH4+ ،K+ and different concentrations of internal solutions were investigated. The electrode exhibited a linear response with a near Nernstian slope of 30.1 ± 0.8 (mV per decade of activity) over the pH range from 3.5 to 7.2 with a satisfactory concentration range of 1.0×10−5 to 1.0×10−1 M. The value of 7.0×10−6 M was obtained as lower detection limit for the fabricated nickel (II) selective electrode. The developed sensor exhibited good reproducibility over a period of about 10 weeks with a fast response time of 15-20 seconds. The proposed sensor was successfully applied as an indicator electrode for the potentiometric titration of a nickel solution with EDTA.