EVANESCENT-WAVE SPECTROSCOPIC STUDIES OF SURFACE-ENHANCED FLUORESCENCE QUANTUM EFFICIENCIES

The techniques of evanescent wave induced fluorescence spectroscopy (E WIFS) and time-correlated single-photon counting have been combined to investigate the photophysical properties of auramine-O at a solid/sol ution interface. Interaction of the dye with the surface causes an enh ancement of the fluorescence quantum efficiency through the restrictio n of intramolecular rotations. The fluorescence kinetics of the adsorb ed molecules are shown to be a function of surface and bulk solution c oncentration. The application of the maximum entropy method to the ana lysis of EWIFS decays is also introduced and discussed. (C) 1995 Acade mic Press, Inc.