DIRECT DETERMINATION OF DIBENZO[A,L]PYRENE IN CRUDE EXTRACTS OF ENVIRONMENTAL-SAMPLES BY LASER-EXCITED SHPOLSKII SPECTROSCOPY

The most potent carcinogenic aromatic hydrocarbon known to date-dibenzo[a,l]pyrene (DB[a,l]P)-has been directly determined in crude extracts of several soil and sediment samples by applying Shpol'skii spectroscopy, a low-temperature high-resolution molecular fluorescence technique. Unambiguous identification and quantitation of DB[a,l]P was possible on the basis of vibrationally resolved fluorescence spectra obtained under site/energy-selective tunable laser excitation and cryogenic sampling conditions. Owing to a relatively long-lived fluorescence of DB[a,l]P, time-resolved fluorescence detection was employed, and a considerable gain in selectivity and sensitivity was achieved. The results obtained, in unfractionated diluted and undiluted n-octane extracts by means of an internal standard procedure, were in a good agreement (repeatability within 15%), DB[a,l]P contents were in the range of tens to hundreds ppb for samples with a different level of pollution.