The ultraviolet (UV) light excited fluorescence spectra of ethanol-water mixture with different concentrations are investigated by derivative fluorimetry. It is found that there are 8 types of luminescent cluster molecules, formed by ethanol and water molecules in different ways, existing in the solution. The peak wavelengths of all these clusters’ fluorescence spectra are measured and their contents are obtained by measuring the peak values in the second derivative fluorescence spectra. The spe
