The Iodide-Selective PVC Membrane Electrode Using a Calix[4]arene Derivative as Ionophore

In this study, a new iodide-selective polyvinyl chloride (pvc) membrane electrode using 5,11,17,23-tetra(tert-butyl)-25,26,27,28-tetra(4-propylimidazole acetamide)-calix[4]arene compound as an ionophore was prepared. optimum membrane composition was found as 2% ionophore, 29.7% pvc and 68.3% o-nitrophenyl octyl ether (o-npoe; plasticizer) by changing the ratio of ionophore, o-npoe and pvc used in the preparation of membrane. the linear working range and the slope of the electrode at ph 4.0 were determined as 1.0×10^-5 – 1.0×10^-2 m and 52.1± 2.6 mv/pi, respectively. it was observed that the proposed electrode had a short response time (5-10 s) and a lifetime of > 5 months. the electrode exhibited selectivity towards different anions in the order of i->salicylate> clo4- > no3- > scn- ≈ benzoate > no2- > br- > cl- > f- > citrate > hcoo-. moreover, the proposed electrode was successfully used as an indicator electrode in the precipitation titration of iodide with silver nitrate.