Hollow carbon nanobubbles-coated solid-phase microextraction fibers for the sensitive detection of organic pollutants

Herein, a novel solid-phase microextraction (SPME)fiber based on hollow carbon nanobubbles was developed for the analysis of persistent organic pollutants. The hollow carbon nanobubbles (HCNBs), derived from the nanoscale zeoliticimidazolate framework (ZIF-8), not only possessed the ZIF-8-like microporous shell but also created an internal space for analytes storage. This architecture was beneficial to accelerating the mass transfer process and enhancing the enrichment capacity towards target analytes. As a result, the sensitivity of this HCNBs based SPME fiber toward analytes (e.g., BTEX, PAHs and PCBs) was 2-180 times higher compared with the commercial fibers (100 μm PDMS, 65 μm PDMS/DVB or 85 μm PA). In addition, owing to the size-selectivity of the microporous shell, the HCNBs-based SPME fiber showed high extraction ability towards target analytes with low molecule weight. Furthermore, the lifespan of the homemade fiber was evaluated to be more than 100 times attributing to the hard and stable carbon framework. Under optimal working conditions, analytical performance of the fiber towards PCBs with varying chlorination degrees showed a wide linear range (0.05-1000 ng L^-1) and low LODs (0.0017-0.0042 ng L^-1). Finally, the established method was successfully applied to the determinations of PCBs in three environmental water samples with good recoveries (84.5-117.1%).