Porous aromatic framework/polydimethylsiloxane coated stir bar sorptive extraction coupled with high performance liquid chromatography-diode array detection of trace polychlorinated biphenyls analysis in environmental waters.

A porous aromatic framework (PAF-47) synthesized through Suzuki coupling reaction was introduced to prepare PAF-47/polydimethylsiloxane (PDMS) coated stir bar by sol-gel technique. PAF-47/PDMS coating provided high extraction recovery (77.6-90.6%, the ratio of actual enrichment factor (EF) to theoretical EF) for five polychlorinated biphenyls (PCBs) in a relatively short time (60 min), exhibiting a faster extraction kinetics over commercial PDMS coating (12/24 h). Based on this, a new method based on PAF-47/PDMS coated stir bar sorptive extraction and high-performance liquid chromatography-diode array detection was proposed for trace analysis of target PCBs in environmental water. Under the optimized conditions, the limits of detection for five PCBs were within 44-70 ng/L, with actual EF of 64.0-71.5-fold (maximal EF of 83.3-fold). This method was successfully used to detect trace PCBs in Yangtze River water and East Lake water, with recoveries of 81.0-113% and 86.1-111%, respectively.

One-pot polymerization of monolith coated stir bar for high efficient sorptive extraction of perfluoroalkyl acids from environmental water samples followed by high performance liquid chromatography-electrospray tandem mass spectrometry detection.

In this work, poly(1-vinylimidazole-ethyleneglycol dimethacrylate) (poly(VI-EDMA)) monolith coated stir bars were synthesized by one-pot polymerization, and they exhibited higher extraction efficiency and faster extraction dynamics for selected PFAAs than commercial ethylene glycol modified silicone (EG-silicone) and polydimethylsiloxane (PDMS) coated stir bars. Taking eleven PFAAs as target analytes, including C4-C12 perfluoroalkyl carboxylates (PFCAs) and C6, C8 perfluoroalkane sulfonates (PFSAs), a method combining monolith-based stir bar sorptive extraction (SBSE) with high performance liquid chromatography (HPLC) - electrospray tandem mass spectrometry (ESI-MS/MS) was proposed for the determination of multiplex PFAAs in environmental water samples. Under the optimized conditions, low limits of detection (0.06-0.40 ng/L) and wide linear range (0.6-400 ng/L) were obtained for target PFAAs with. The developed method was then applied for the analysis of target PFAAs in environmental water samples, and recoveries of 80.1-117% and 80.3-122% were obtained for target PFAAs in spiked Yangtze River and East Lake water samples respectively.