Theoretical and practical investigations of copper ion selective electrode with polymeric membrane based on N,N′-(2,2-dimethylpropane-1,3-diyl)-bis(dihydroxyacetophenone)

A novel ion-selective poly(vinyl chloride) (PVC) membrane sensor for Cu2+ ions based on N,N'-(2,2-dimethylpropane-1,3-diyl)-bis(dihydroxyacetophenone) (NDHA) as a new ionophore was prepared and studied. The best performance was observed for the membrane composition, including 30:65:1:4 (wt%) = PVC:DBP:KTpCIPB:NDHA. The electrode showed a good Nernstian slope of 30.0 +/- 0.5 mV/decade in a wide linear range activity of 3.0 x 10(-7) to 1.0 x 10(-2) mol dm(-3) Cu(NO3)(2) with limit of detection 2.5 x 10(-7). Sensor exhibited a fast response time (t(95%) < 10 s) and could be used for about 4 months in the pH range of 3.0-7.4. The proposed potentiometric sensor was found to work satisfactorily in partially non-aqueous media up to 30 (vol%) content of methanol, ethanol and acetone. Applications of this electrode for the determination of copper in real samples, and as an indicator electrode for potentiometric titration of Cu2+ ion using EDTA, were reported. In order to predict the extraction ability of NDHA for different metallic ions, the complexes [M(NDHA)] and [M(H2O)(6)] (where M = Cu2+, Co2+, Hg2+, Pb2+, Ag+, Mg2+, Ca2+, Mn2+, Zn2+, Cd2+, K+ and Al3+) were investigated using ab initio theoretical calculations. The metal binding capability was evaluated using the binding energy. Results of our study could be useful for prediction of the extraction power of this Schiff base and could play a guiding role in planning experiments. (C) 2011 Elsevier Ltd. All rights reserved.