Polycyclic aromatic hydrocarbons (PAHs) in ambient aerosols from Beijing: characterization of low volatile PAHs by positive-ion atmospheric pressure photoionization (APPI) coupled with Fourier transform ion cyclotron resonance.
Aromatic fractions derived from aerosol samples were characterized by gas chromatography and mass spectrometry (GC-MS), high temperature simulated distillation (SIMDIS), and positive-ion atmospheric pressure photoionization (APPI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), respectively. It was found that about 27 wt % compounds in aromatic fractions could not be eluted from a GC column and some large molecule PAHs were neglected in GC-MS analysis. APPI FT-ICR MS was proven to be a powerful approach for characterizing the molecular composition of aromatics, especially for the large molecular species. An aromatic sample from Beijing urban aerosol was successfully characterized by APPI FT-ICR MS. Results showed that most abundant aromatic compounds in PM2.5 (particles with aerodynamic diameter ≤ 2.5 μm) were highly condensed hydrocarbons with 4-8 aromatic rings and their homologues with very short alkyl chains. Furthermore, heteroatom-containing hydrocarbons were found as the significant components of the aromatic fractions: O1, O2, N1, and S1 class species with 10-28 DBEs (double bond equivalents) and 14-38 carbon numbers were identified by APPI FT-ICR MS. The heteroatom PAHs had similar DBEs and carbon number distribution as regular PAHs.
State Key Laboratory of Heavy Oil Processing, China University of Petroleum , Beijing 102249, People's Republic of China.
Bin
B
Jiang
Yongmei
Y
Liang
Chunming
C
Xu
Jingyi
J
Zhang
Miao
M
Hu
Quan
Q
Shi
D000336:Aerosols / Q000032:analysis*; D001274:Atmospheric Pressure; D002681:China; D002849:Chromatography, Gas / Q000379:methods; D017357:Cyclotrons; D005583:Fourier Analysis; D006358:Hot Temperature; D013058:Mass Spectrometry / Q000379:methods; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis*
D000336:Aerosols; D011084:Polycyclic Aromatic Hydrocarbons