Ag+-selective poly(vinyl chloride) Membrane Electrode Based on [N,N'- ethylenebis-(3-methoxy salicylaldimine)]

A solid state silver selective poly (vinyl chloride) (PVC) membrane electrode was developed by using recently synthesized [N, N'-ethylenebis-(3-methoxy salicylaldimine)] as an active component of the membrane. The best sensitivity and selectivity for Ag+ ions were obtained for the electrode membrane containing ionophore-NPOE-PVC and KTpClTB in composition of 4:62:33:1 (w/w). The proposed electrode had a Nernstian response (56.0 mV/decade) to Ag+ within the concentration range 1.0 ×10-6 to 1.0×x10-1 mol L-1and with a detection limit of 8.3×10-7 mol L-1. The electrode worked well between pH 3.0 and 8.0 and had a fast response time of 15 s. The electrode was used along 3 months without any significant change in its sensitivity. Potentiometric performance of the electrode in partially non-aqueous medium (up to 10 % (v/v) alcohol) was found satisfactory. The electrode was successfully used in the potentiometric titration of silver ions with standard solution of potassium iodide, and in the direct determination of silver ion in spiked waste water and photographic film developing solutions.