| In recent years,porous organic framework?POF?material attracted considerable attention due to its rich synthesis reaction type,controlled pore structures,modifying functional groups diversification.POF materials have potential application in many fields,especially in terms of gas adsorption and separation.Solid-phase microextraction?SPME?is a kind of sample pretreatment technology that uses solid adsorbent to enrich the analyte in the sample.The use of POF material as a functional adsorbent for the SPME extraction head is expected to increase the effect of SPME and broaden the application of POF materials,which has a very good research value and application prospects.In this paper,POF fibers with different structural characteristics were made into high-quality SPME fibers for detection of volatile organic compounds?VOCs?,and the relationship between POF microstructure and SPME effects was discussed.First,a novel SPME fiber suitable for the detection of styrene and benzenes was prepared.It was fabricated by a POF material?PAF-48?bonded to a gel material through a sol-gel process in quartz fiber.PAF-48 is an aromatic POF polymerized from 1,3,5-triphenylbenzene.The uniform pore size,high specific surface area,regulatable structure and superior hydrophobicity make PAF-48 expected to great potential to have special abilities to absorb and extract styrene as well as benzenes.In this paper,PAF-48/Gel-coated fiber was converted into SPME extraction head and used in conjunction with gas chromatography?GC?to establish an analytical method for the determination of styrene and six benzene homologues?benzene,toluene,ethylbenzene and xylene?from aqueous food simulants.The method has a wide linear range(0.1–200?g·kg-1 or 0.1–500?g·kg-1),a low detection limit(LOD,0.003–0.060?g·kg-1)with high accuracy and the fiber have a very long life?>200 times?.Particularly for styrene,the PAF-48/Gel-coated fiber exhibited a much lower LOD(0.006?g?kg-1)compared with most of the reported fibers.Moreover,the PAF-48/Gel-coated fiber had a high extraction selectivity for styrene and benzenes over alcohols,phenols and alkanes.Finally,the PAF-48/Gel-coated SPME fiber was successfully applied in GC for the determination of the specific migrations of styrene and benzenes from polystyrene?PS?plastic food contact materials.Second,another POF material?JUC-Z2?selected as the functional coated SPME fibers suitable for aromatic amine detection were prepared by the same sol-gel method.The JUC-Z2-coated SPME fiber was combined with gas chromatography-mass spectrometry/mass spectrometry?GC-MS/MS?,and a direct analysis method without any derivatization step was developed for the determination of two aromatic amines in urine samples.The new method exhibited satisfactory linearity in the wide range of0.01–100?g?L-1 with correlation coefficients?R?of 0.9999.The limits of detection are both 0.01 ng?L-1.The relative standard deviations for repeated extraction?n=6?with one fiber are less than 7.7%.The JUC-Z2-coated fiber demonstrates obvious superiority for extracting the two aromatic amines over the commercial fibers.To deeply investigate the structure-activity relationship,the extraction performances of JUC-Z2 for 1-naphthylamine and 2-naphthylamine were compared with those of porous aromatic framework-48?PAF-48?,respectively.JUC-Z2 and PAF-48 have a similar two-dimensional layered structure,and the specific surface area and pore size are also similar;but the adsorption effect on aromatic amines is quite different.This is due to the fact that the JUC-Z2 framework is rich in N atoms and can interact with the amino group of the analyte aromatic amine,whereas PAF-48 is a full benzene ring structure and lacks such a driving force.These results indicate that the surface chemical environment of the porous material is of significance and value for the adsorption of the target molecules.Finally,JUC-Z2 coated SPME fiber has been successfully used to detect 1-naphthylamine and 2-naphthylamine in the urine of smokers. |
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