Low-pressure gas chromatography–ion trap mass spectrometry for the fast determination of polycyclic aromatic hydrocarbons in air samples

Abstract

A low-pressure gas chromatography–ion trap mass spectrometry (LPGC–ITMS) method was investigated to shorten the analysis time for 18 US Environmental Protection Agency priority listed polycyclic aromatic hydrocarbons (PAHs). Their elution was optimised with a short, wide-bore column coupled to a deactivated capillary at the inlet end and with a long, conventional column to compare their analytical performance. The analytical figures of merit under optimal LPGC–ITMS conditions were determined with respect to chromatographic separation, S/N ratio, limit of detection and precision. The peak width at half height of 1.5 s matched the ITMS duty cycle. Up to 16 PAHs in the molecular weight (MW) range of 128–278 Da could be separated in a very short time, i.e. less than 13 min using LPGC–ITMS, whereas with conventional GC–MS, it took approximately 40 min. However, LPGC–ITMS has a limited loss of separation power compared to that of conventional GC–MS due to the occurrence of three critical pairs for high-MW PAHs. For a practical evaluation, the LPGC–ITMS approach was applied to the determination of PAHs in gas and aerosol phase samples collected in the ambient air of Hasselt, Belgium.