Recently, owing to the performance improvement of the headspace (HS)-sampling devices and its consumables, HS vial samples can be analyzed at temperatures up to 300°C. Some studies have attempted to analyze polycyclic aromatic hydrocarbons (PAHs) in atmospheric 2.5 μm particulate matter (PM 2.5) collected on a filter paper by gas chromatography/mass spectrometry (GC/MS) coupled with thermal desorption device. However, no studies have reported the use of an HS-sampling device to quantify PAHs in PM 2.5 filter paper. In this study, we found that the quantification of PAH analysis using HS-GC/MS can be improved by the following steps, so that the accuracy becomes almost the same as that of a solvent-extraction method: 1) replacement of the air in the HS vial with nitrogen, 2) limiting the solvent to toluene, 3) using the hydrolyzed polyimide-covered septum, and 4) optimization of the heating temperature and heating time of the HS vial. As a result, we succeeded in protecting PAHs in an HS vial at a high temperature and in creating an analysis method with a high recovery rate and high repeatability; the limit of quantitation of each PAH in this method was 5.4 pg m-3 in the case of a volume of 10080 m3 of air being collected on the filter paper.
Keywords: HS-GC/MS; PAHs; PM 2.5; hydrolyzed polyimide septum; thermal extraction.