Development of an analytical method for indoor polycyclic aromatic hydrocarbons and their halogenated derivatives by using thermal separation probe coupled to gas chromatography-tandem mass spectrometry.

Polycyclic aromatic hydrocarbons (PAHs) and their halogenated derivatives (XPAHs) have been a concern because of their high toxicity. Monitoring indoor PAHs and XPAHs concentrations is important for risk assessment because humans typically spend >90 % of their time indoors. However, the background levels of indoor PAHs and XPAHs concentrations are unknown because of the low sensitivity of conventional analytical methods. In this study, we developed a highly sensitive analytical method using a thermal separation probe (TSP) coupled to a gas chromatograph with a triple quadrupole mass spectrometer method for 26 PAHs and 40 XPAHs. The method quantification limit (MQL) values of the TSP method were 1.1 (3,8-dichlorofluoranthene)-906 (dibenzo[a,e]pyrene) times lower than those of the conventional method. The regression line comparing the TSP and conventional methods was y = (0.944 ± 0.0401)x, which was in good agreement. These results demonstrate that the TSP method can be applied to indoor air analysis. The total concentrations of PAHs and XPAHs were 944 and 73.5 pg m for the house and 735 and 0.924 pg m in the office, respectively. Among the detected compounds, 13 PAHs and XPAHs could not be detected using conventional methods because of their high MQL values. The composition of total toxicity equivalency values in the house was dominated by dibenzo[a,i]pyrene (DBaiP: 43.2 %) and dibenzo[a,h]pyrene (DBahP: 27.1 %), which could not be detected using the conventional method. Therefore, the TSP method can improve the risk assessment of indoor PAHs and XPAHs.