Partition of Europium(III) with β-diketones and neutral additives between micellar and bulk phases in aqueous nonionic surfactant solutions

The dstribution ratio of europium(III) with a β-diketone and a neutral adduct between micellar and bulk phases in aqueous nonionic surfactant solution was measured by a spectrofluorimetric method as a function of hydrogen ion concentration. The synergic effect of trioctylphosphine oxide for the various β-diketone chelates is much greater than that of tributyl phosphate.