Use of a Natural Sorbent as Alternative Solid-Phase Microextraction Coating for the Determination of Polycyclic Aromatic Hydrocarbons in Water Samples by Gas Chromatography-Mass Spectrometry

In this study, the use of bracts as a natural sorbent in solid-phase microextraction was exploited for use in the determination of polycyclic aromatic hydrocarbons in water samples with separation/detection performed by gas chromatography-mass spectrometry. Fiber-to-fiber reproducibility was evaluated and the relative standard deviation (RSD) was lower than 14%. Optimizations were performed using both the proposed and DVB/Car/PDMS (divinylbenzene/carboxen/polydimethylsiloxane) fibers. The optimum extraction conditions were 80 min of extraction at 50 ºC with 12% (m/v) NaCl for the bract fiber, and 100 min of extraction at 80 ºC for the commercial fiber. The limits of detection and quantification for the proposed fiber were, respectively, 0.003 and 0.01 µg L-1 for fluorene, phenanthrene, anthracene and pyrene, and 0.03 and 0.1 µg L-1 for acenaphthylene, benzo(a)anthracene and chrysene. The method using bract fiber provided relative recoveries ranging from 68 to 117%, intraday and interday precisions lower than 17 and 19%, respectively, and extraction efficiency similar to that of the DVB/Car/PDMS fiber.