Spectrophotometric determination of polynuclear aromatic hydrocarbons in airborne particulates

Abstract

The separation and identification of polycyclic aromatic hydrocarbons in airborne particulates is important because some of these hydrocarbons have been found to be carcinogenic to man. They are present in combustion sources, cigarette smoke and in coal-tar pitch. The polycyclic hydrocarbons were extracted from dust with benzene. These air particulates were collected from heating unit filters in a Youngstown building. The hydrocarbons in the benzene-soluble fraction were then separated by two-dimensional dual-band thin-layer chromatography. All these steps were done in the dark to avoid the photochemical decomposition of the compounds. The locations of the hydrocarbons in the chromatoplate were detected by their fluorescence in ultraviolet light. The hydrocarbons were then extracted with methanol. The ultraviolet-visible absorption spectra of the methanol extracts were determined from 220 to 460 nm with a Cary 14 recording spectrophotometer. The absorption spectra of the isolated polycyclic aromatic hydrocarbons were compared with available standards. The Rf values of both standards and samples using 26 per cent acetylated cellulose as the adsorbent were also determined. Benzo(a)pyrene which is a strong carcinogen has been identified. Benz(a)anthracene, a weak carcinogen, is also present. The other polycyclic aromatic hydrocarbons identified are coronene, benzo(g,h,i)perylene, perylene, benzo(b)fluoranthene and, possibly, a pyrene derivative.