Abstract

We describe the use of frequency-domain phase-modulation fluorometry to determine time-resolved emission decay kinetics. Using newly constructed instruments (1,2) we measured the frequency-dependent phase angles and demodulation factors at frequencies ranging from 1 to 200 MHz. Such data were obtained for two and three-component mixtures of fluorophores. Two decay times were easily recovered if they differed by a factor of two, and a three-component mixture was resolved with decay times of 1.3, 4.4 and 12. nsec. Measurement at several emission wavelengths enhanced our ability to resolve closely spaced two and three-component decays.

© 1984 Optical Society of America