Uranyl salophenes as ionophores for phosphate-selective electrodes

Anion selectivities of poly(vinylchloride) (PVC) plasticized membranes cont aining uranyl salophene derivatives were presented. The influence of the me mbrane components (i.e. ionophore structure, dielectric constant and struct ure of plasticizer, the amount of incorporated ammonium salt) on its phosph ate selectivity was investigated. The highest selectivity for H2PO4- over o ther anions tested was obtained for lipophilic uranyl salophene III (withou t ortho-substituents) in PVC/o-nitrophenyl octylether (o-NPOE) membrane con taining 20 mol% of tetradecylammonium bromide (TDAB). Ion-selective electro des (ISEs) based on these membranes exhibited linear response in the range 1-4 of pH(2)PO(4)(-) with a slope of 59 mV/decade. The introduction of orth o-methoxy substituents in ionophore structure decreased the phosphate selec tivity of potentiometric sensors. (C) 2000 Elsevier Science S.A. All rights reserved.