Preparation of environmental samples for the determination of polycyclic aromatic hydrocarbons by thin-layer chromatography.

An evaluation of extraction procedures, liquid-liquid distribution systems, Sep-Pak cartridges, liquid-solid chromatography using silica, alumina and chemically modified silica packings (acid-base treated ethylammonium nitrate and picric acid impregnated), macroreticular resins and gel permeation columns for the analysis of polycyclic aromatic hydrocarbons (CPAHs) in environmental samples by thin-layer chromatography is discussed. For particulate samples solvent extraction using a Soxhlet apparatus or ultrasonication was found to be preferable to sublimation and liquid-liquid distribution between hexane and dimethyl sulfoxide followed by silica gel column chromatography was the preferred method for sample clean-up. Using this procedure enabled six PAHs (anthracene, fluoranthene, benz[a]anthracene, perylene, pyrene, and coronene) to be determined quantitatively in urban air particulate, diesel engine exhaust particulate, laboratory ventilator dust, household dust, river water, and tea samples. The PAHs were identified by coincidence of retention between the sample and standards in the same chromatographic system and by adequate agreement with standards for their normalized emission response ratios. The two-point calibration method was used for quantitation. Good agreement for the concentration of PAHs in the air particulate and diesel particulate extracts with published data using gas chromatography-mass spectrometry and high-performance liquid chromatography was found.