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.

本研究开发了以苞片作为天然吸附剂的固相微萃取（solid-phase microextraction）技术，结合气相色谱-质谱联用法（gas chromatography-mass spectrometry）进行分离与检测，用于水样中多环芳烃（polycyclic aromatic hydrocarbons）的定量分析。本研究评估了纤维间重现性，其相对标准偏差（relative standard deviation, RSD）低于14%。分别采用自制萃取纤维与DVB/Car/PDMS（divinylbenzene/carboxen/polydimethylsiloxane）商业萃取纤维开展优化实验。其中，自制苞片萃取纤维的最优萃取条件为：50℃下萃取80 min，氯化钠添加量为12%（m/v）；商业萃取纤维的最优萃取条件则为80℃下萃取100 min。自制苞片萃取纤维的检出限与定量限分别为：芴、菲、蒽及芘的检出限为0.003 μg·L⁻¹，定量限为0.01 μg·L⁻¹；苊烯、苯并(a)蒽及屈的检出限为0.03 μg·L⁻¹，定量限为0.1 μg·L⁻¹。采用苞片萃取纤维的分析方法的相对回收率介于68%~117%之间，日内精密度与日间精密度分别低于17%与19%，萃取效率与DVB/Car/PDMS商业纤维相当。