Ion-selective polymeric-membrane electrodes with immobilised ion-exchange sites. Part I. Development of a calcium electrode

Abstract

A new type of ion-selective electrode is described in which ion-exchange sites are immobilised in a polymeric membrane by covalent bonding. Membranes were prepared by cross-linking a styrene-butadiene-styrene triblock copolymer with triallyl phosphate. After subsequent hydrolysis these membranes were evaluated as Ca²⁺ sensors. The electrodes formed exhibited an extended Nernstian response to Ca²⁺(10^–1– 10^–6M) and good selectivity over other alkaline earth and alkali metals. Such electrodes offer very fast response times, extended lifetimes and a wide pH working range. The possibilities of this new class of ion-selective electrode are also discussed.