Abstract

Polycyclic aromatic hydrocarbons are ubiquitous in nature present in petroleum products in varying concentrations. They are
used as a marker for chemical fingerprinting of crude oil, adulteration detection of kerosene in petrol and diesel, source liability
determination in environmental contamination, and oil spill cases. In forensic investigation chromatographic methods used
are expensive and increases cost of analysis per sample. Hence, replacement of chromatographic technique with low cost,
simple, and sensitive method of analysis is required. Conventional fluorescence spectroscopy and synchronous fluorescence
spectroscopy (SFS) method was compared for their application in forensic study. Pure kerosene, diesel and petrol samples,
and six different brands of diesel samples were analyzed with conventional method. Six diesel samples were analyzed with
developed SFS method. For adulteration detection, diesel sample was simulated with kerosene sample 0.1 to 50% concentration
and then analyzed with SFS. Conventional fluorescence spectroscopy does not show sharpness in fluorescence intensity, whereas
SFS shows well separated sharp fluorescence intensity peaks. As the concentration of kerosene increases in the diesel, it causes
self-quenching of diesel fluorescence, subsequently decreasing the intensity of fluorescence spectra. From present study, it is
concluded that synchronous spectrofluorimetry needs to be developed and included in forensic laboratories for routine petroleum
product analysis that can replace traditional method of analysis.