Frequency-Domain Lifetime Measurements Using ChronosFD™Yevgen Povrozin and Ewald Terpetschnig
ChronosFD is the first, frequency-domain fluorescence lifetime instrument that enables measurement of time-resolved data using laser diodes (LDs) and light emitting diodes (LEDs) as excitation sources. This powerful instrument provides all the benefits of a full lifetime fluorometer but at an affordable price. ChronosFD is fully automated using Vinci, a Windows-based software package and is upgradeable to do steady-state measurements.
In order to demonstrate the flexibility of ChronosFD we have measured several fluorescent compounds with these LED and LD light sources. Measurement of these compounds on ChronosFD is fast and easy. Switching light sources can be done in a matter of minutes. LEDs and LDs provide excellent light sources with large modulation depth - up to 100% at certain frequencies, and they can be easily modulated up to 250 MHz (some up to 500 MHz). In this context we would like to refer you to the ISS Application Note: Frequency Domain Spectroscopy Using 280nm and 300nm LEDs.
All measurements were performed on ChronosFD, the modular lifetime fluorometer from ISS.
|ANS free||τ1 = 0.250 ns,||τ2 = 3.55 ns,||f1 = 0.87|
|ANS+BSA (2mg/mL)||τ1 = 16.83 ns,||τ2 = 3.02 ns,||f1 = 0.83|
Literature data : Two components for BSA-bound ANS: τ1 = 16 ns, τ2 = 2-4 ns for DP=1/1.
Literature data : Average lifetime for Chlorophyll: 1.2 ± 0.5 ns.
Literature data : Average lifetime (EB bound to DNA): 23 ns.
Literature data : Lifetime of free EB: 1.7 ns (single exponential).
Literature data : lifetime = 367 ns (single exponential, air).
Literature data : 9.32 ns (single exponential) in toluene.
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