Liventsova O. Determination of preservatives and antioxidants with the use of sensitized luminescence of lanthanide ions.

Thesis is devoted to the justification of the use of sensitized luminescence of Eu (III) and Tb (III) ions in sorbates of complexes with a preservatives (benzoic, sorbic and dehydroacetic acids) and antioxidants (vanillin, gallic acid and antibiotics of quinolone series) for their sorption-luminescence determination. Sorption and luminescence properties of complexes of Eu (III) and Tb (III) with benzoic acid and 1,10 - phenanthroline or 2, 2'- dipyridyl on the TLC plates and silicagel has been studied. It has been found that in the sorbates of complexes there are several possible ways of the excitation energy transfer to the ion Ln (III). It has been shown, that in sorbates of complexes effect of the ligand field is most pronounced that is expressed through the splitting of HST and the redistribution of the intensities of f-f transitions. Herewith the symmetry of the coordination sphere of the ion Ln (III) is changed as well that is manifested in the change of both the HST intensity ratio and magnetic dipole transitions. The optimum conditions of sorption complex Tb (III)-DHA on zeolite and plates for TLC have been determined. It is shown that TOPO and Twin-80, increasing luminescence intensity are outside the inner sphere of the complex, and they have a hydrophobic effect. The quenching mechanism for the luminescence sensor Tb (III)-TOPO in the presence of Triton X-100 and sorbic acid has been studied. Found effect has been used to determine the sorbic acid. The interaction of vanillin with ions Tb (III), as well as the sorption of this complex and the complex of Tb (III) with gallic acid on the TLC plate have been studied for the first time. Organic solvents, surfactants do not affect luminescence intensity sorbates. It is shown that luminescence of Tb (III) sorbate - gallic acid increases in the presence of TOPO, providing hydrophobic effect on the molecule of the complex. The conditions of absorption and luminescence properties of sorbate complexes Eu (III) and Tb (III) with antibiotics - norfloxacin, ofloxacin, ciprofloxacin and lomefloxacin, as well as luminescence properties of the complexes Tb (III) with lomefloxacin in the solution have been studied. It is shown that in the sorbate complexes effect of anionic surfactants on luminescence intensity is much less pronounced as compared with solutions, and effect of the ligand field is the most pronounced, which may be associated with a rigid fixation of complex in phase of sorbent. The possibility of applying of all the studied sorbate complexes as new analytical forms for solid-phase luminescence determination of series of preservatives and antioxidants has been shown.