A capillary fluorometer was constructed using a 2 mW, 365 nm ultraviolet (UV) light emitting diode (LED) as the excitation source and a new-generation high-gain (3×108) channel photomultiplier tube. The use of a LED permitted rapid pulsing of the excitation source so that the instrument could be employed for time-resolved fluorescence (TRF) applications. A detection limit of ∼2×108 molecules of BHHT (4,4′-bis (1″,1″,1″,2″,2″,3″,3″-heptafluoro- 4″,6″-hexanedion-6″yl)-o-tephenyl)-Eu (III) were resolved within a 1.25 nanoliter volume at a S/N ratio of 3:1. Ultimate sensitivity of the system was compromised due to visible luminescence emitted by the UV LED, centred around 550 nm extending to > 700 nm and 2nd-order exponentially decaying with lifetimes of 40 μs and 490 μs.
|Number of pages||9|
|Journal||Progress in Biomedical Optics and Imaging - Proceedings of SPIE|
|Publication status||Published - 2005|