Nontarget Screening of Polycyclic Aromatic Compounds in Atmospheric Particulate Matter Using Ultrahigh Resolution Mass Spectrometry and Comprehensive Two-Dimensional Gas Chromatography.

Polycyclic aromatic hydrocarbons (PAHs) are mutagenic and carcinogenic. 16 PAHs as priority pollutants listed by the US Environmental Protection Agency were usually monitored. Therefore, multiple potentially toxic polycyclic aromatic compounds (PACs) are not monitored. In this study, atmospheric particulate matter samples from Beijing were analyzed using atmospheric pressure photoionization (APPI) Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry and comprehensive two-dimensional gas chromatography-time-of-flight (GC × GC-TOF) mass spectrometry. The FT-ICR data detected high molecular weight PAHs, alkylated PAHs (APAHs) and heteroatom PAHs. The GC × GC-TOF data tentatively identified 386 PACs in five categories of identification confidence. Twenty-one spectra in the unknown class were manually resolved. Eighty-two PACs with high identification confidence were proposed for further research. The identities of five PAHs and five APAHs that are currently not regulated were confirmed using available standards and quantified in some samples. Some of these PACs, such as dibenzo[a,e]pyrene (CH) and 1-methylpyrene (CH), should be of concern because of their contamination levels and the high toxicities of themselves and/or their derivatives. This study highlights the possibility of expanding the traditional lists of PAHs to improve pollution control and risk assessment accuracy.