Novel PVC-membrane Potentiometric Sensors based on 2-Amino-N-(2-Mercapto phenyl) Benzamid for Silver Ion

A new highly selective silver (i) electrode was prepared with a pvc membraneusing 2-amino-n-(2-mercapto phenyl) benzamid (l) as an electroactive material, 2-nitrophenyloctylether (o-npoe) as a plasticizer and sodium tetraphenylborate (natpb) as anadditive in the percentage ratio of 3:5:57:35 (natpb:l:o-npoe:pvc, w:w). potentiometricevaluation of the poly(vinyl chloride) (pvc) membranes containing l showed excellentaffinity and selectivity to silver (i) ion over alkali, alkaline earth and other transition metalcations. these electrode works well over wide range of concentration (1.0×10-2 to 1.0×10-7m) with a nernstian slope 59.1±0.2 mv/decade. the potentiometric responses areindependent of the ph of the test solution in the ph range 2.9–10.3. the electrodes possessadvantages of low resistance, fast response time and relatively long lifetimes. the electrodeswere used, as indicator electrodes, in the potentiometric titration of silver ion and in thedetermination of ag+ in waste water.