title: Analytical application of the co-fluorescence effect in detection of europium, terbium, samarium and dysprosium with time-resolved fluorimetry.
abstract: Application of the co-fluorescence effect has been examined for the simultaneous detection of the lanthanide ions Eu(3+), Tb(3+), Sm(3+) and Dy(3+). In the presence of Y(3+) and 2,2'-bipyridine (BP), the fluorescence intensities of the pivaloyltrifluoroacetone chelates of these lanthanides were greatly enhanced by an inter-chelate energy transfer process. Under optimized conditions, the following detection limits were obtained; 0.019 pM for Eu(3+), 0.27 pM for Tb(3+), 3.8 pM for Sm(3+) and 20 pM for Dy(3+), when a sensitive time-resolved fluorometer was used for the measurement. A co-fluorescence based fluorescence enhancement solution was also tested in a dual-label time-resolved immunofluorometric assay of luteinizing and follicle stimulating hormones (LH and FSH) based on the use of Eu(3+) and Tb(3+) as the label ions. The present fluorometric detection system is particularly well suited for multilabel time-resolved fluorometric immunoassays utilizing two, three or four ion labels simultaneously.
authors.affiliation: Institute of Atomic Energy of China, Analytical Chemistry Laboratory, P.O. Box 275-88, Beijing, China; Wallac Biochemical Laboratory, P.O. Box 10, 20101, Turku, Finland.
authors.forename: Y Y
authors.initials: YY
authors.lastname: Xu
authors.forename: I A
authors.initials: IA
authors.lastname: Hemmilä