A PVC Membrane Electrode for Zirconium Based on 4-Nitrophenylazo-n-(2-hydroxypropylamine) Salicylidine
A potentiometric zirconium sensor based on the use of 4-nitrophenylazo-N-(2-hydroxypropylamine)salicylidine (NHPS) as an ion carrier in poly (vinyl chloride) (PVC) matrix, was developed. The best performance was observed for the membrane composition including 26.27% PVC, 65.67% N-POE, 5.43% NaTPB and 2.63% ionophore.The electrode which can be used for at least 1 month without observing any deviation exhibited a Nernstian slope of 29.37 mV per decade and a linear range of 1.0×10-2 to2.0×10-7 mol L-1, with a detection limit of 2.0×10−8 mol L−1, for zirconium ion. Also it showed a fast response time of about 10 s. The proposed membrane sensor revealed good selectivity for zirconium ion over a wide variety of other metal ions and could be used in pH range of 5–9.5. It was successfully used as an indicator electrode in potentiometric titration of zirconium ion.
Keywords: Ion selective electrode; Zirconium; Potentiometry; Schiff base.