Poly(vinyl chloride) matrix membrane uranyl ion-selective electrodes based on cyclic and acyclic neutral carrier sensors

Uranyl ion-selective electrodes (ISEs) have been fabricated from poly(vinyl chloride) matrix membranes containing four different neutral carrier ionophores, namely, 1,11-bis(2-benzyloxy-5-formylphenoxy)-3,6,9-trioxaundecane (A), bis[(12-crown-4)-2-ylmethyl] 2-dodecyl-2-methylmalonate (B), bis[(benzo-15-crown-5)-15-ylmethyl] pimelate (C) and N, N'-bis[(ll-ethoxycarbonyl) undecyll]- N, N', 4,5-tetramethyl-3,6-dioxaoctane diamide (ETH 1001) (D). These were used with either 2-nitrophenyl octyl ether or dioctylphenyl phosphonate (DOPP) as plasticising solvent mediators. The most favourable sensor was A, especially when an anion excluder (sodium tetraphenylborate) was included in the DOPP-based cocktail for ISE membrane construction, as this showed reduced interference from iron(III). Selectivity coefficients were determined for 16 inorganic cations and dynamic response times during spiking calibrations were <1 min.