Determination of Vanadyl Ions by a New PVC Membrane Sensor Based on N, N'-bis-(Salicylidene)-

N, N'-bis-(salicylidene)-2,2-dimethylpropane-1,3-di- amine (NNPD) was found to be a suitable neutral ion carrier for the construction of a highly selective and sensitive vanadyl membrane sensor. Poly(vinyl chloride) (PVC) based membranes of NNPD with potassium tetrakis (p-chlorophenyl) borate (KTpClPB) as an anionic excluder and diethyl sebacate (DES), dibutyl phthalate (DBP), banzyl acetate (BA) and -nitrophenyloctyl ether (NPOE) as plasticizing solvent mediators were investigated in vanadyl membrane sensors. A membrane, composed of NNPD-PVC-KTp- ClPB-DES with the ratio 4.0:30.0:1.0:65.0, works well over a wide concentration range (7.0 10 to 1.0 10 M) with a Nernstian slope of 28.8 0.3 mV per decade of activity between pH values of 4.0 and 5.10. The detection limit of the sensor was calculated to be 5.0 10 M. It displays satisfactorily good discrimination toward vanadyl ions with regard to most common transitional metal ions. The proposed sensor demonstrates a short response time ( 10 s). It was successfully applied for the determination of vanadyl ions in water samples.