Quantitative determination of 16 polycyclic aromatic hydrocarbons in soil samples using solid-phase microextraction

A method for the determination of polycyclic aromatic hydrocarbons (PAHs) in soil samples using ultrasonic-assisted extraction with internal surrogates combined with solid-phase microextraction and GC-MS has been developed. Five kinds of commercial solid-phase microextraction fibers, 100 microm PDMS, 30 microm PDMS, 65 microm PDMS/DVB, 50 microm DVB/CAR/PDMS and 85 microm PA, were compared to choose the optimal SPME fiber for extraction of PAHs. One hundred micrometers of PDMS fiber was found to be more suitable for the determination of PAHs due to its wider linear range, better repeatability, lower detection and more satisfactory efficacy than the other fibers. Under the recommended conditions, 100 microm PDMS fiber could provide low nanogram level detection limits with correlation coefficient greater than 0.98. The method was also applied to determine PAHs in a spiked soil sample, obtaining recoveries higher than 79.3%. A field study with naturally contaminated samples from local contaminated sites was carried out. The proposed method was found to be a reliable, inexpensive and simple preparation method for quantitative determination of 16 PAHs in soil samples.