A lower rim functionalised calixarene molecule 5,11,17,23-tetra-tert-butyl-
25,27-bis(hydroxy)-26-(ethoxycarbonylmethoxy)-28-(diethyl carbamoyl-methoxy
) calix[4]arene, which was originally developed for solid phase extraction
of trace uranium from environmental and industrial waste water, is tested a
s a possible ionophore in ion selective electrodes (ISEs). PVC based membra
nes containing the calix[4]arene were used in experiments to test the chara
cteristics and viability of these sensors. The electrodes gave more stable
potential readings when used around neutral pH 5.5-8.5. Extraction experime
nts using the PVC membranes showed that the calix[4]arene complexed with:th
e uranyl species end extracted it from the test solutions most effectively
at around pH 7.0. The limit of detection for uranium species, around 1 ppm
under normal conditions, was avoided by preconditioning the membranes at hi
gh pH. The effect of testing for uranium selectivity amongst a matrix of ca
tions and anions in a simulated waste solution showed that interference was
significant. As we are at the beginning of this research, suggestions for
further work on these electrodes are made in light of recent reports of wor
k in this field. (C) 2001 Published by Elsevier Science B.V.