Porous aromatic framework coated stir bar sorptive extraction coupled with gas chromatography for the analysis of 16 polycyclic aromatic hydrocarbons in atmospheric particles and environmental water samples.

In this work, porous aromatic frameworks (PAFs) with different pore size were evaluated for simultaneous adsorption of 16 polycyclic aromatic hydrocarbons (PAHs) with large difference in polarity and molecular size. Two other porous organic polymers containing electron pushing/withdrawing group were investigated along for a comparison, and PAF-120 with the pore size of appr. 2.1 nm exhibited the highest extraction efficiency. Based on water contact angle and molecular dynamics simulation, the adsorption of 16 PAHs on PAF-120 was attributed to hydrophobic interaction, π-π interaction and molecular sieving effect. PAF-120/PDMS coated stir bar was then prepared by physical adhesion, and a method of stir bar sorptive extraction-gas chromatography-flame ionization detector was established for trace PAHs analysis in environmental samples. Under the optimal experimental conditions, the limits of detection (S/N = 3) for 16 PAHs were found to be in the range of 42-375 ng/L, with the relative standard deviations of 4.1-14.6% (n = 7). The enrichment factors varied from 31 (Indeno[1,2,3-cd]pyrene) to 80-fold (anthracene), with the maximal enrichment factor of 100-fold. The proposed method was applied to the analysis of PAHs in local environmental water and atmospheric particle samples. None of the 16 PAHs were detected in the collected water samples. While for the collected atmospheric particles, 12 PAHs were detected in fine particulate matter (PM) within the range of 0.6-2.8 ng/m. For inhalable particulate matter (PM) and total suspended particulate matter (TSP), 16 PAHs were all detected in the range of 0.6-3.8 ng/m and 0.6-5.9 ng/m, respectively. Quantitative recoveries were obtained in recovery test, demonstrating the accuracy and application potential of the proposed method.