Selective Electrochemical Sensor for Silver(I) Ion Based on Chelating Ionophore o-Hydroxyacetophenone Carbohydrazone (OHAC)

Novel polymeric membrane electrode based on o-hydroxyacetophenone carbohydrazone (OHAC) as a neutral ionophore carrier has been prepared and explored as silver(I) ion selective electrode. The addition of lipophilic anion excluder (NaTBP) and various plasticizers viz. o-nitrophenyl octyl ether (o-NPOE), dibutyl phthalate (DBP) and butyl acetate (BA) have found to improve the performance of membrane sensor which have a composition of I:NaTBP:NPOE:PVC in the ratio 3:2:62:33 (w/w; mg). The electrode exhibit Nernstian slope for silver (I) ions over wide concentration ranges from 1.0×10-7 M to 1.0×10-2 M with limits of detection 1.6×10-7 M. The response time was found to be 10 s. The potentiometric responses were independent of the pH of the test solutions in the pH range of 3.0 to 8.0. The proposed electrode revealed good selectivity over a wide variety of other cations including alkali, alkaline earth, transition and heavy metal ions. The proposed PVC electrode was used as an indicator electrode in the potentiometric titration of Ag+ ions with KI and NaCl solutions and in direct determination in different water samples and urine sample of peoples working as jewelry maker.