Fabrication and characterization of metal organic frameworks/ polyvinyl alcohol cryogel and their application in extraction of non-steroidal anti-inflammatory drugs in water samples.

A series of novel MOFs/PVA composite cryogel (MIL-101(Cr)/PVA, MIL-100(Fe)/PVA, ZIF-8(Zn)/PVA, MOF-199(Cu)/PVA and MIL-53(Al)/PVA) were fabricated by using a facile and green freeze-thaw approach for the first time. MIL-101(Cr)/PVA cryogel was selected as a VA-SPE sorbent for extraction of four NSAIDs in environmental water samples. The procedures of condition investigation (synthesis and extraction optimization) and characterization were also performed. And a satisfactory result of methodology validation was obtained by making use of HPLC-MS/MS. Under the optimum conditions, good sensitivity levels were achieved with the limits of detection between 0.007 and 0.037 μg L-1 , a linearity of 0.10-10 μg L-1 for phenylbutazone, indomethacin, nimesulide and 0.020-2.0 μg L-1 for benorilate (r2 ≥ 0.9934). The relative recoveries of the target analytes were in the range from 78.44% to 105.7% with relative standard deviation (RSD) from 1.33% to 9.85%. In the extraction process, MIL-101(Cr)/PVA cryogel as a whole sheet outperformed the pristine dispersive MIL-101(Cr) in separation from solvent, and the application of cryogel also simplified the operation procedure. Additionally, the combination of PVA with MOFs might strengthen the interaction ability between the sorbent and analytes. This novel pretreatment method had a variety of merits, such as easy operation, high enrichment efficiency and low matrix effect. It looks forward to further optimization or functionalization and application of these MOFs/PVA cryogel in various disciplines.