Cesium-selective optode membrane based on the lipophilic calix[4]biscrown in the 1,3-alternate conformation.

One type of lipophilic calix[4]biscrowns in the 1,3-alternate conformation which are highly selective complexant for cesium has been used to construct cesium poly(vinyl chloride) (PVC) membrane optode. The reversible sensing system has been formed by incorporating the lipophilic neutral H(+)-selective chromoionophore ETH5294 in the plasticized PVC membrane with 1,3-calix[4]bisnaphtyl-crown-6. The measuring range of cesium ions can be conditioned by buffering different pH in the cesium solutions. At pH 7.0, the measuring range of the optode membrane for cesium ions is from 1x10(-6) to 1x10(-2) M. The response behavior of optode membrane including response time, selectivity, reproducibility and lifetime, has been described in detail.