A PVC-based 1,8-diaminonaphthalen electrode for selective determination of vanadyl ion

A PVC membrane vanadyl (VO²⁺) ion-selective electrode was constructed using 1,8-diaminonaphthalen (DAN) as a neutral carrier. The electrode shows good Nernstian response for VO²⁺ ions over a wide concentration range (1.0×10⁻¹-1.0×10⁻⁵ M). The optimum composition of the membrane was 55 wt.% poly(vinylchloride), 35 wt.% 2-nitrophenyl octyl ether (NPOE), 5 wt.% ionophore, and 5 wt.% potassium tetrakis(p-chlorophenyl)borate (KTpClPB). It has relatively fast response time and can be used at least for 5 weeks without any considerable divergence in potentials. The proposed electrode revealed relatively good selectivity for VO²⁺ over wide variety of other metal ions. The electrode was used for the potentiometric titration of VO²⁺ ions with EDTA.