Determination of particulate polycyclic aromatic hydrocarbons in ambient air by gas chromatography-mass spectrometry after molecularly imprinted polymer extraction

A solid phase extraction procedure (SPE) is described for the quantitative analysis of poly cyclic aromatic hydrocarbons (PAHs) in atmospheric particulate matter (PM),as ubiquitous environmental pollutants routinely measured in air quality monitoring.A SPE cartridge was used based on a molecular imprinted polymer (MIP-SPE) properly tailored for selective re tention of PAHs with 4 and more benzene fused rings.The performance of the clean-up procedure was evaluated with the specific concern of selective purification towards satu rated hydrocarbons,which are the PM components mostly interfering GC analysis of targe PAHs.Under optimized operative conditions,the MIP-SPE provided analyte recovery close to 95%for heavier PAHs,from benzo(α)pyrene to benzo(ghi)perylene,and close to 90%fo four benzene rings PAHs,with good reproducibility (RSDs:2.5%-5.9%).Otherwise,C17-C32n-alkanes were nearly completely removed.The proposed method was critically compared with Solid Phase Micro Extraction (SPME) using a polyacrylate fiber.Both methods were suc cessfully applied to the analysis of ambient PM2.5samples collected at an urban polluted site.Between the two procedures,the MIP-SPE provided the highest recovery (R%≥93%) fo PAHs with 5 and more benzene rings,but lower for lighter PAHs.In contrast,SPME showed a mean acceptable R%value (～80%) for all the investigated PAHs,except for the heavies PAHs in the most polluted samples (R%:110%-138%),suggesting an incomplete purification from the interfering n-hydrocarbons.