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

摘要

A solid phase extraction procedure(SPE)is described for the quantitative analysis of polycyclic aromatic hydrocarbons(PAHs)in atmospheric particulate matter(PM),as ubiquitous environmental pollutants routinely measured in air qualitymonitoring.A SPE cartridge was used based on a molecular imprinted polymer(MIP-SPE)properly tailored for selective retention 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 saturated hydrocarbons,which are the PM components mostly interfering GC analysis of target 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%for four benzene rings PAHs,with good reproducibility(RSDs:2.5%-5.9%).Otherwise,C_(17)-C_(32) n-alkanes were nearly completely removed.The proposed method was critically compared with Solid Phase Micro Extraction(SPME)using a polyacrylate fiber.Both methods were successfully applied to the analysis of ambient PM2.5 samples collected at an urban polluted site.Between the two procedures,the MIP-SPE provided the highest recovery(R%≥93%)for 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 heaviest PAHs in the most polluted samples(R%:110%-138%),suggesting an incomplete purification from the interfering n-hydrocarbons.