Liquid polymeric membrane composition of ion selective electrode based on thiazole-4-carboxamide as ionophore

Thiazole-4-carboxamide (Th) has been prepared as ionophore in an electrochemical setup of a cadmium ion selective electrode (ISE). There are four components in liquid polymeric membrane consist of thiazole-4-carboxamide (Th) as an ionophore, polyvinyl chloride (PVC) as a polymeric matrix, sodium tetra phenyl borate (NaTPB) as an ionic additive and benzyl acetate (BA) as a plasticizer. An experiment is conducted using various different composition of the membrane. Result shows the optimum ratio of Th:PVC:NaTPB:BA is 5.0:30.0:2.0:63.0 by weight percentage. The Nernstian response for Cd2+ that obtained the best response at a range pH 5.20-5.72 is having a slope of 29.4±1.1 mV per decade with a linear working range 1.0×10−7 to 1.0×10−4. However, the worst Nernstian response for Cd2+ at the same range of pH is having a slope of 15.7±0.6 mV per decade with linear working range of 1.0×10−4 to 1.0×10−2 and using 0.0:33.0:2.0:65.0 as a ratio of Th:PVC:NaTPB:BA by weight percentage.