Determination of polycyclic aromatic hydrocarbons in the needles of a Scotch pine (<Emphasis Type="Italic">Pinus sylvestris</Emphasis> L.), a biomonitor of atmospheric pollution

A procedure was developed for the determination of polycyclic aromatic hydrocarbons (PAH) in the needles of a Scotch pine (Pinus sylvestris L.), which is characterized by the simple and efficient sample preparation. The procedure involves the steps of the extraction of PAH with n-hexane on ultrasonic irradiation, the precipitation of concomitant cereous components from the extract on its cooling, the purification of the PAH fraction on a cartridge with silica gel (0.5 g), and the redissolution of the concentrated eluate in methanol. The quantitative determination of PAH (15 compounds including 13 priority) with the use of chromatography-mass spectrometry in the selective ion detection mode exhibits the interlaboratory precision of the results of the PAH determination V _Rl = 0.059–0.088 for the concentration of PAH in needles from 0.3 to 600 ng/g and a detection limit of 0.06 ng/g (signal-to-noise ratio = 3; mass of the sample for extraction was 10 g). The accumulation levels of PAH in the Scotch pine needles were presented; the needles were first studied as a biomonitor of atmospheric pollution over the southern part of the Baikal natural territory.