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 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.

Modified Coated Copper Wire as a New Fiber for SPME-GC Analysis of Some Polycyclic Aromatic Hydrocarbons

In this study for the first time, a novel copper Solid Phase Microextraction (SPME) fiber has been introduced for removal of naphthalene, phenanthrene and anthracene from aqueous solution. Copper was used as a solid support, which was at first coated by 3-mercaptopropyltrimethoxysi- lane. A stationary phase of oxidized multi walled carbon nanotube (MWCNTs)) was bonded to the surface of the copper wire. The developed SPME was characterized by IR and Scanning Electron Microscopy (SEM) and coupled to gas chromatography for separation of the analytes. Stability of the fiber, the effect of coating thickness and recovery time were optimized. The MWCNTs film thickness was about 5 μm which was perfect for a rapid mass transfer. The detection limits were at the range of 0.005 to 0.1 μg·L-1. The calibration curves were linear R2 > 0.9813 in the range of 0.01 to 5 μg·L-1. The method has been successfully applied for real samples with standard addition of 5 μL-1 of each sample. Stability study of the fiber to acid and alkali shows that it can be used for more than 50 times.