trFluor(TM) Eu donkey anti-rat IgG (H+L) *Cross Adsorbed*

Many biological compounds present in cells, serum or other biological fluids are naturally fluorescent, and thus the use of conventional, prompt fluorophores leads to serious limitations in assay sensitivity due to the high background caused by the autofluorescence of the biological molecules to be assayed. The use of long-lived fluorophores combined with time-resolved detection (a delay between excitation and emission detection) minimizes prompt fluorescence interferences. Our trFluor(TM) Eu probes enable time-resolved fluorometry (TRF) for the assays that require high sensitivity. trFluor(TM) Eu probes have large Stokes shifts and extremely long emission half-lives when compared to more traditional fluorophores such as Alexa Fluor or cyanine dyes. Compared to the other TRF compounds, our trFluor(TM) Eu probes have relatively high stability, high emission yield and ability to be linked to biomolecules. This trFluor(TM) Eu donkey anti-rat IgG (H+L)conjugate is commonly used as a second step reagent for indirect immunofluorescent staining, when used in conjunction with biotinylated primary antibodies. It is a very valuable tool for biotin-streptavidin-based biological assays and tests using TR-FRET platform.