Determination of polycyclic aromatic hydrocarbons in commercial liquid smoke flavorings of different compositions by gas chromatography-mass spectrometry.

The presence of polycyclic aromatic hydrocarbons (PAHs) in five commercial liquid smoke flavorings, used in the European food industry, was studied. The samples were subjected to an alkaline treatment, extracted with cyclohexane, cleaned up by means of solid-phase extraction tubes, and analyzed by gas chromatography-mass spectrometry. Three different procedures for the cleanup were tested. The results revealed the presence of 34 PAHs, some of them with methyl substituents. In all cases, the concentrations of compounds of low molecular weight were much higher than those of high molecular weight. Relationships between smoke flavoring compositions and PAH levels were also studied. Three of the samples contained high levels of both total and carcinogenic PAHs. Benzo[a]pyrene was also detected in these three samples, but its concentration did not exceed the 10 microg/kg level fixed by the FAO/WHO. Finally, a relation was found, first between the concentrations of total carcinogenic PAHs and benzo[a]pyrene and also between the concentrations of pyrene and benzo[a]pyrene. The latter ratio reveals that pyrene concentration could be very useful in predicting the level of benzo[a]pyrene and, consequently, in estimating the carcinogenicity arising from the presence of benzo[a]pyrene and other carcinogenic PAHs.