Trapping of polycyclic aromatic hydrocarbons in vehicle exhaust using an in-tube extraction device for analysis by gas chromatography-barrier ionization discharge detection

Abstract

This work presents a methodology for polycyclic aromatic hydrocarbons (PAHs) trapping from vehicular emissions using an in-tube extraction device (IT-FEx). Trapping selectivity studies were conducted, evaluating the interaction profile between the aromatic compounds and the polymeric phase (composed of polydimethylsiloxane and internal to the IT-FEx devices), as in an aqueous equilibrium system (25 min of sampling), and as in gaseous dynamic phase (30 s of sampling), regarding a qualitative evaluation. The adsorption profiles were similar, with greater affinity for medium-sized PAHs (four aromatic rings) than for the smaller (one to three rings) and larger (five to six rings). The device was attached to a vehicle emission sampler to evaluate the qualitative emission of diesel-powered vehicles. Certain PAHs, such as phenanthrene, fluoranthene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, and benzo[k]fluoranthene, were effectively trapped by the IT-FEx device and detected by the GC-BID analysis. Finally, it was possible to develop a process that combined the steps of sample preparation and instrumental analysis, using the IT-FEx device and applying it to the gaseous matrix in the dynamic phase; until then, little was elucidated regarding the use of this apparatus. This sampling device, combined with analysis by gas chromatography with a barrier ionization discharge detector (GC-BID), is a powerful tool for identifying many compounds from vehicular emissions and does not require solvents in sample preparation.

Keywords: Diesel emission; Dynamic phase sampling; Gas chromatography with barrier ionization discharge detector; IT-FEx; PAHs.