Development of an optimized gas chromatography / triple quadrupole mass spectrometry method for the quantitative determination of nitro- and oxygen containing polycyclic aromatic hydrocarbons (N-/ O-PAHs) in atmospheric samples

Abstract

Nitrated and oxygenated polycyclic aromatic hydrocarbons (nitro-/oxy-PAHs) are organic pollutants which are released to the atmosphere from incomplete combustion processes, or formed by degradation of their parent PAH compounds. Nitro- and oxy-PAHs are present in the atmosphere at trace levels, but are shown to have potential of being highly carcinogenic and mutagenic and therefore represent a significant health threat even at low concentrations. In this study, three methods of identifying the presence of nitroand oxy-PAHs have been researched and tested. Before negative ion chemical ionization (NICI) became broadly available for GC/MS analysis, electron ionization (EI) ion sources was used for identification and quantification of PAHs. EI provides more excessive fragmentation, and therefore a higher sensitivity for the identification than the ionization method, which is usually applied for nitro- and oxy-PAH analysis today, NICI. The EI ion source was tested with a 60 m WAX-column in order of achieving improved sensitivity and selectivity compared to formerly applied methods. This method did not offer sufficient sensitivity or selectivity to provide an alternative to the established methods, however, as the EI ion source gave too excessive fragmentation for identification, and the chromatograms had many peaks, implying impurities from the column.