Polar Forms of Benzo[a]pyrene May Be Ubiquitous in the Environment

Previously, we reported that polar polycyclic aromatic compounds (polar PAC) can be detected by first oxidizing them with KO2/O2 and then detecting the carboxylic acid products, after pentafluorobenzylation, by gas chromatography electron capture mass spectrometry (Allam et al. Anal. Chem. 1992, 65, 1723−1727). For example, we used the method in the cited study to detect a benzo[a]pyrene tetrahydrotetraol hydrolysis product derived from benzo[a]pyrene-exposed lymphocytes after isolation of the DNA. However, the method was limited in its sensitivity by the presence of an interfering, analyte-like peak in the final mass chromatograms. Now, the results of our current work strongly suggest that the contamination leading to the unwanted peak is ubiquitous in the urban environment. Results from the analysis of a standard reference sample of urban particulate matter (SRM 1649) yielded a level of 10 ng of contaminant in a 5-mg sample (2 μg/g). The concentration of this polar contaminant is comparable to the certified value for benzo[a]pyrene of 14.5 ng (2.9 μg/g). Furthermore, our mass spectral data show evidence for the presence of many other polar PAC in the sample. These observations add to the concern raised by related environmental health studies focused on the potential impact of airborne polar PAC on human health.