Bn. Barsoum et al., Evaluation of some new 14- and 15-crown-formazans as carriers in cesium ion selective electrodes, TALANTA, 47(5), 1998, pp. 1215-1222
A number of new crown-formazans with 14 and 15 membered rings have been inv
estigated as selective neutral carriers in cesium ion selective electrodes.
Two plasticizers (NPOE and NPBnE) were studied. The new 14-crown-formazan
4a containing the 4-pyridyl N-oxide at the formazyl carbon exhibited the hi
ghest selectivity in cesium ion selective electrodes, especially towards th
e two low selectivity monovalent ions K+ and NH4(+). Also, membranes contai
ning the plasticizer NPBnE showed better cesium selectivity relative to mos
t ions than those containing NPOE. Membranes containing 4a and variable com
positions of plasticizers, potassium tetrakis-(p-chlorophenyl)borate (KTpCl
PB), and trioctylphosphine oxide (TOPO) were studied in order to prepare an
electrode with the optimum cesium selectivity. The highest selectivity for
cesium was achieved with the two electrodes designated d and e with membra
nes containing the ionophore 4a, NPBnE and KTpClPB with and without TOPO. S
electivities are reported relative to sodium, potassium, barium, calcium, a
mmonium, lithium, cobalt, and magnesium. (C) 1998 Elsevier Science B.V. All
rights reserved.