Multicomponent Fluorometric Analysis Using a Fiber-Optic Probe

Single-frequency phase-resolved fiuorometry through single and bifurcated fiber-optic probes is used to quantify mixtures of spectrally similar fiuorophores. Correlation coefficients from correlation plots are greater than 0.98, and standard errors of estimate are less than 0.13 μM for 80 binary mixtures. Quantification of fiuorophores at up to 10:1 molar ratios with lifetime separations of less than 200 ps is possible. The simultaneous quantification of the individual components of ternary and quaternary synthetic mixtures is demonstrated. Application of phase resolution to ambient light rejection is reported also. In this case, the emission spectrum of 10 nM Rhodamine 6G is easily obtained in the presence of a fluctuating, unmoduiated background.