Resolved fluorescence emission spectra of PRODAN in ethanol/buffer solvents.

The fluorescence steady-state emission spectra of lipophilic fluorescence probe PRODAN in ethanol/buffer solvents of different concentrations (0.3, 0.9, 3 mol L(-1) ethanol) were extensively studied and analytically described. The complex experimental spectra, corrected for background effects, were fitted by two Gaussian curves. The energy separation of two maxima, (0.147+/-0.002) eV at 37 degrees C and (0.143+/-0.003) eV at 25 degrees C, was independent of ethanol concentration. The blue shifts observed for both maxima were linearly dependent on solvent polarity. The linear dependences of fluorescence's intensities on PRODAN concentration in all ethanol/buffer solvents indicate that no PRODAN self-quenching takes place even at the highest measured PRODAN concentrations.