Determination of zinc(II) ions in waste water samples by a novel zinc sensor based on a new synthesized Schiffʹs base

A highly selective and sensitive zinc ion-selective membrane electrode based on N,N′-phenylenebis (salicylideaminato) (L) as a new carrier is reported. The membrane is composed of poly (vinyl chloride) (PVC), o-nitrophenyl octyl ether (NPOE) as plasticizer, potassium tetrakis(p-chlorophenyl) borate (KTpClPB) as lipophilic ionic additive, and L as sensing material. The proposed electrode displays a Nernstian response to Zn2+ ions over a wide concentration range of 5.0 × 10− 7–1.0 × 10− 1 M with the slope of 29.4 ± 0.2 mV per decade and a detection limit of 2.6 × 10− 7 M. The sensor has a relatively fast response time of < 10 s and it can be used in the pH range of 3.0–7.0 for at least 2 months without any significant divergency in potential. The selectivity coefficients for mono-, di-, and trivalent cations indicate the good selectivity of sensor for Zn2+ ions over a large number of interfering cations. As a result the proposed electrode was applied to Zn2+ ions determination in mixture solutions and wastewater samples.