Comparison of extraction methods for the determination of polycyclic aromatic hydrocarbons in soot samples

The results of the analysis of polycyclic aromatic hydrocarbons (PAH) in soot and similar types of sample are often dependent on the extraction method applied, owing to carbonaceous substances present in these samples. The recoveries of three extraction methods, and ultrasonic ether, a Soxhlet toluene and a Soxhlet extraction with liquid CO2 were compared for a typical soot sample. Additionally the CO2 extraction was optimized with respect to the necessary number of transfers during the extraction and the proper method to remove the CO2 after extraction. Finally, the liquid chromatographic pretreatment of the extract, prior to gas chromatographic analyses of the PAH, was improved.