A highly selective chromoionophore for potassium based upon a bridged calix[4]arene
Abstract
The chromoionophores 9 and 10 in chloroform extract potassium ions from aqueous solutions in the pH range 7–9 with high selectivity as compared with sodium (KeK+/KeNa+ca. 1000), magnesium and calcium (no detectable extraction) ions.