Capsule phase microextraction of selected polycyclic aromatic hydrocarbons from water samples prior to their determination by gas chromatography-mass spectrometry

Capsule phase microextraction (CPME) is a recently introduced environmentally friendly sample preparation technique that integrates both filtration and stirring mechanism into the extraction device. In this study, CPME was employed for the first time for the extraction of four polycyclic aromatic hydrocarbons (naphthalene, fluorene, phenanthrene and pyrene) from water samples prior to their determination by gas chromatography-mass spectrometry (GC-MS). The microextraction capsules were made of two porous polypropylene tubes that are welded to each other; one tube contained the magnetic rod, and the other tube contained the sorbent. Various sol-gel hybrid sorbents were evaluated. Microextraction capsules containing sol-gel poly(caprolactone)-poly (dimethylsiloxane)-poly(caprolactone) (PCAP-PDMS-PCAP) sorbent provided the highest extraction efficiency. The main parameters (e.g., adsorption time, sample volume, stirring rate, addition of salt, type of eluent, desorption time and elution volume) affecting the steps of the CPME procedure were evaluated. Under the selected conditions, limits of detection (signal/noise = 3.3) ranged between 0.03 and 0.07 ng mL-1 for the selected PAHs. The relative standard deviation for the within-day and between-days repeatability were lower than 7.7% and 8.5%, respectively. Moreover, the CPME method exhibited good linearity and reusability of the microextraction capsules. The method was successfully applied to the analysis of tap water, mineral water and lake water samples. Relative recoveries ranged between 94.3 and 109.8%. The herein reported green method could efficiently simplify the overall sample preparation process, since it overcomes the requirements of sample filtration before the extraction and the solvent evaporation and sample reconstitution after the extraction.