Kiriiak G. Increase of both sensitivity and selectivity of Tb(III), Dy(III), Pr(III) and Eu(III) luminescent determination in the presence of accompanying lanthanides

Оbject of investigation: the Tb(III), Dy(III), Pr(III), Eu(III) complexes with organic ligands. Aim of investigation:search for methods enhancing luminescence intensity of Tb(III), Dy(III), Pr(III) and Eu(III) complexes in the presence of accompanying lanthanides with the aim to increase both sensitivity and selectivity of their luminescent determination. For the first time the analytical forms sorption from water-dimethylsulfoxide solutions as well as isolation of short-lifetime luminescence component of determined lanthanide was used. Methods of investigation and instruments: spectrophotometry, IR-spectroscopy, luminescence spectroscopy and time-resolved luminescence. Results: TThe possibility search for methods enhancing luminescence intensity of Tb(III), Dy(III), Pr(III) and Eu(III) complexes in the presence of accompanying lanthanides with the aim to increase both sensitivity and selectivity of their luminescent determination. For the first time the analytical forms sorption from water-dimethylsulfoxide solutions as well as isolation of short-lifetime luminescence component of determined lanthanide was used.Pyrazol-5-carbonic acids were used for the first time to luminescence sensitization of Tb(III) and Dy(III). It has been found that at the removal of non-radiative energy losses by sorption of complex from solution Н2О-DMSО (50% vol.) the detection limit of Tb(III) in complexes with pyrazole derivatives can be decreased in ? 100 times.With the use of time-resolved luminescence through the isolation of short-lifetime luminescence Dy(III) component its determination in presence Tb(III) was realized for the first time. The realized systematic research on the luminescence of complexes Pr(III) with various ?-diketones proves that only in case of complex compounds with thenoylacetone derivatives in luminescence spectra band with the maximum at 605 nm, free of Sm(III) and Eu(III) bands is observed. Pr(III) in luminescent materials with the detection limit 1х10-3 % was determined with the use of mixed-ligand complex Pr(ТТА)3DAPМ. In result of suppression of non-radiative energy losses the detection limit Pr(III) was decreased from 0,01 to 0,0002 mkg/ml.Sensitive method for the Eu(III) determination in samarium oxide of high purity was developed with the use of photostable to UV-radiation of sorbate of complex Eu(III) with nalidixic acid on zirconium phosphate. Detection limit of Eu(III) is 1х10-5 %, that is two order lower as compared to the known method of its determination in solution of complex with ТТА and Phen (4х10-3 %).Field of application: analytical chemistry.