Enhanced luminescence of the europium(III) - terbium(III) -dibenzoylmethane - ammonia - acetone system and its application to the determination of europium

The enhanced luminescence of the Eu-dibenzoylmethane(DBM)-NH3 system in the presence of Tb3+ and the effect of solvents on that system in the absence of Tb3+ were studied. The optimum conditions for co-luminescence of the Eu-Tb-DBM-NH3 system were examined. The optimised procedure was applied to the determination of trace amounts of Eu. The detection limit is 4.0 x 10-11M, which is about two orders of magnitude lower than that of the system in the absence of Tb. An intermolecular transfer of energy from the enhancing complex to the fluorescing complex is proposed. (author)