Detection and identification of polyaromatic hydrocarbons (PAHs) contamination in soil using intrinsic fluorescence

Polyaromatic hydrocarbons (PAHs), such as pyrene, benzo[a]pyrene, phenanthrene, and anthracene induce toxic, carcinogenic, and mutagenic effects on living organisms and are considered as primary pollutants. Traditional methods for their identification are often laborious and time-consuming and do not account for the heterogeneous nature of their distribution. Here we present confocal microscopy as a rapid and accurate technique for direct analysis of PAHs in soil samples without the complexity of sample pre-processing which might delay results for several days. The method uses the intrinsic fluorescence of PAHs for detection and their emission spectra for the identification of different PAHs. A clear difference was observed in the fluorescence spectral properties of phenanthrene, pyrene and naphthalene in real-time environmental samples. The post-processing of confocal scans obtained in the detection stage of PAHs was completed through the application of ImageJ software. Intrinsic fluorescence-based detections of PAHs may open new avenues in terms of rapid detection and identification of PAHs in heterogeneous complex soil samples.