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

Fluorescence emission spectra and quantum yields have been measured for neat sample of six different hydrocarbon fuels over different possible excitation wavelengths. Hydrocarbon fuels show different excitation fluorescence cutoff depending on their commercial use and applications in the UV ∼ visible region. The fluorescence emission maximum of these fuels shows a red shift with excitation wavelength. Resonance energy transfer and self-quenching through solvent collision of fluorophores play an important role on the fluorescence characteristics of multifluorophoric mixture like petroleum fuels at higher concentration. The fluorescence quantum yield of these fuels is a function of the excitation wavelength and is different for different fuels. The change in quantum yield with excitation wavelength for petroleum fuels is different from that of crude oils. The change in fluorescence quantum yield at lower excitation wavelength provides a promising tool to estimate contamination of diesel and petrol by kerosene.