[Sampling and preliminary treatment of polycyclic aromatic hydrocarbons for analysis].

This review deals with the different methods of sampling of paticulate matter, either suspended or sedimentable, the extraction of the contained carcinogenic hydrocarbons and the pretreatment necessary to allow a good quantitative determination of these potentially hazardous substances. The sampling may be done by filtering a certain volume of air or collecting the sedimentable materials in deposit gauges. In the first case, filters of various nature and porosity are used and the volume of air to be filtered may vary between large limits; but the trend is now to use high volume samplers, two types of which are described. To extract the organic matter from the collected particulates, various solvents may be used, at their boiling point in a Soxlhet apparatus, or at ambiant temperature with the aid of ultra-sonic waves. The solutions, which contain many undesirable products, have to be subjected to a preliminary treatment in order to obtain a purified sample of the compounds to be determined. These treatments include washing with alcaline and acidic aqueous solutions to remove the impurities having phenolic or basic character. Finally, the prepurified solutions may be subjected to various chromatographic procedures, in order to make group separations which simplify the final identification and determination of the individual components present in the initial mixture.