A novel ‘ionic liquid-mediated multi-walled car- bon nanotube (MWCNT)-poly(dimethylsiloxane) (PDMS)’ hybrid coating was prepared by the covalent functionalization of MWCNTs with hydroxyl-terminated PDMS using the sol– gel technique. The prepared fiber was successfully used for the separation and determination of trace amounts of polycyclic aromatic hydrocarbon compounds (PAHs) in four urine samples using head-space solid-phase microextraction cou- pled to gas chromatography-flame ionization detection. The proposed fiber has high thermal stability and long durability and it can be used more than 210 times without any significant change in its sorption properties. The effects of important parameters such as the exposure time, sampling temperature, sample ionic strength and stirring rate on the extraction effi- ciency have been studied and optimized. Under the optimal conditions, the method detection limits ( S / N =3) were in the range of 0.0005–0.004 ng mL -1 and the limits of quantifica-tion ( S/N=10) between 0.002 and 0.01 ng mL-1.Therela-tive standard deviations for one fiber (repeatability, n=5)were 4.9–7.5 % and for the fibers obtained from different batches (reproducibility, n =3), 6.1–8.9 %. The developed method was successfully applied to determine trace levels of PAHs in real urine samples. The obtained relative recoveries for the spiked samples with 0.05 ng mL -1 of each of the PAH compounds were 89.3–107.2 %.

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