Excitation dependent fluorescence quantum yield in hydrocarbon fuels containing polycyclic aromatic compounds

Fluorescence emission spectra and quantum yields have been measured for nea t sample of six different hydrocarbon fuels over different possible excitat ion wavelengths. Hydrocarbon fuels show different excitation fluorescence c utoff depending on their commercial use and applications in the UV similar to visible region. The fluorescence emission maximum of these fuels shows a red shift with excitation wavelength. Resonance energy transfer and self-q uenching through solvent collision of fluorophores play an important role o n the fluorescence characteristics of multifluorophoric mixture like petrol eum fuels at higher concentration. The fluorescence quantum yield of these fuels is a function of the excitation wavelength and is different for diffe rent fuels. The change in quantum yield with excitation wavelength for petr oleum fuels is different from that of crude oils. The change in fluorescenc e quantum yield at lower excitation wavelength provides a promising tool to estimate contamination of diesel and petrol by kerosene.