Luminescence determination of europium microquantities after its preconcentration on polyurethane foam

Sorption of the mixed-ligand complexes of europium(III) with thenoyltrifluoroacetone (TTA) and 1,10-phenanthroline (Phen) on polyurethane foam (PUF) has been studied by a luminescence method. The optimum conditions of sorption have been found. The sorbate composition on PUF has been determined (the Eu:TTA:Phen ratio was 1:3:1). Luminescence spectra of the europium complexes in solution and on PUF at 77 K have been investigated. It was concluded that the character of the Eu³⁺ coordination both in solution and on the sorbent is the same. Stability constants for the complexes in solution (lg K = 8.4) and on the sorbent (lg K = 5.5) have been calculated. The decrease of the stability of the complex on PUF is explained by the deformation of the complex molecule in the sorbent phase. Sorption coefficients for europium (245) and scandium (2.35) and the coefficient of selectivity for europium in Sc₂O₃ (102.3) have been determined. A method for the sorption-luminescence determination of europium in Sc₂O₃ with a lower limit of contents determined of 1 × 10^?60% has been developed.