Determining sub-cooled liquid vapor pressures and octanol-air partition coefficients for chlorinated and brominated polycyclic aromatic hydrocarbons based on gas chromatographic retention times: Application for gas/particle partitioning in air

Abstract

Halogenated polycyclic aromatic hydrocarbons (Halo-PAHs) are a new group of PAH derivatives and are reported to be more toxic than their parent PAHs. However, limited research has been undertaken on their physicochemical properties. In this study, sub-cooled liquid vapor pressures (P-L) and octanol-air partition coefficients (K-OA) of 24 chlorinated and 11 brominated PAHs (C1PAHs and BrPAHs) were determined using the gas chromatographic retention time (GC-RT) technique. The temperature dependences of P(L )and K-OA for the Halo-PAHs were determined by the slopes and intercepts of the linear regressions. The GC-RT method also provided the enthalpies of vaporization (Delta H-L) and internal energies of phase transfer (Delta U-OA) for all interested compounds. The activity of Halo-PAHs in octanol (gamma(oct)) ranging from 18 to 87, indicated the non-ideal solution behavior. The number of the chlorine atoms in the PAH rings could influence the interaction of C1PAHs with the organic matter, whereas this interaction for BrPAHs could not be studied due to the limited number of target BrPAHs. The measured values of P-L and K(OA )were applied to investigate the gas/particle partition behaviors of Halo-PAHs in Ulsan, South Korea. This study is so far the first one to report the linear regression coefficients, which can be used to estimate the P (L) and K-OA values of Halo-PAHs at any temperature.