CHARACTERISTICS OF A EUROPIUM-SELECTIVE ELECTRODE BASED ON A CALIX[4]ARENE TETRAPHOSPHINE OXIDE

A poly(vinyl chloride) (PVC) electrode containing a calix[4]arene phosphine oxide [calix-(OCH(2)CH(2)PoPh(2))(4)] as the ionophore which is selective for Eu-III in the presence of a high background of Na+ and other common ions is described. The selectivity and response of this electrode is compared with that of an electrode incorporating the tetramethyl ester calix[4]arene by injection experiments. Flow injection is also used to demonstrate the selectivity of the tetraphosphine oxide calix[4]arene for europium(III).