Liquid–liquid extraction of Eu(lll) using synergic mixture of 1-phenyl-3-methyl-4-trifluoroacetyl-2-pyrazolin-5-one and crown ethers

Synergic extraction of Eu(III) as representative of rare earth elements was conducted with 0.01 mol dm−3 of trifluoroacetyl-pyrazolin-5-one (HPMTFP) and then with synergic mixture of HPMTFP and crown ethers (benzo-15-crown-5, 18-crown-6, 15-crown-5) in dichloromethane (DCM) from aqueous solution having pH 1.0–3.5. Slope analysis method was used for determining the composition of the synergic adduct i.e. Eu(PMTFP)3 that came out to be Eu(PMTFP)3·2S, where S = neutral oxo-donor and -PMTFP = conjugate base of HPMTFP molecule. Selective extraction of Eu(III) was found in the presence of various masking agents like citrate, oxalate, bromide, thiosulphate, chromate ions and of some cations. The accuracy of the developed procedure was checked by analyzing real lake sample (IAEA-SL-3) as a reference material.