title: An evaluation of solvent mediators for ion-selective electrode membranes based on calcium bis(dialkylphosphate) sensors trapped in poly(vinyl chloride) matrices.
abstract: This study on several alkan-1-ols, di-n-octylphenyl phosphorate and di-n-nonyl phthalate as solvent materials in ion-selective electrode membranes based on calcium bis(dialkylphosphate) sensors trapped in a PVC matrix indicates that the best electrodes are made with di-n-octylphenyl phosphonate. These are selective for calcium. The liquid alcohols readily exude from the PVC matrix, and solid alcohols are completely unsuitable for membrane fabrication. However, despite a tendency to be exuded, decan-1-ol gives acceptable electrodes responsive to bivalent cations if calcium bis (di-2-ethylhexylphosphate) is used as sensor. Several selectivity coefficients, k(caj), greater than unity were found, but though such values for j = Na or K do not involve complete loss of selectivity towards calcium, a value of K(CaCu) = 13 for a membrane with di-n-nonyl phthalate as mediator and calcium bis(di-n-decylphosphate) as sensor indicates greater selectivity for copper than for calcium.
authors.affiliation: Chemistry Department, UWIST, Cardiff CF1 3NU, WalesU.K.
authors.forename: A
authors.initials: A
authors.lastname: Craggs
authors.forename: L
authors.initials: L
authors.lastname: Keil
authors.forename: G J
authors.initials: GJ
authors.lastname: Moody
authors.forename: J D
authors.initials: JD
authors.lastname: Thomas