| Bisphenols(BPs)are environmental endocrine disrupting chemicals which have been widely used in food packaging materials due to their good mechanical properties,heat resistance and elasticity.However,BPs are easy to migrate to food and cause pollution.Human intake of BPs can cause endocrine system disorders,nervous system damage and risk of disease increase,so it is very important for the enrichment and determination of BPs in food.Covalent organic frameworks(COFs)have the characteristics of high porosity,large specific surface area,good stability,high reusability and strongπconjugated system.In this paper,COF@Tp-NDA withβ-ketoenamine bond was synthesized by 1,3,5-trialdehyde phloroglucinol(Tp)and 1,5-diaminonaphthalene(NDA),and modified with hollow fiber(HF)and stainless steel wire to prepare HF extraction bar and solid-phase microextraction(SPME)fiber,respectively.A fast and efficient membrane protection/electric drive/microextraction method for BPs in complex samples was established.The methods were developed for the determination of five BPs(bisphenol F,bisphenol A,bisphenol B,bisphenol AF and bisphenol Z)in beverages and canned meat by high performance liquid chromatography with fluorescence detector and gas chromatography with flame ionization detector.The main research contents and results are as follows:(1)The HF extraction bar was designed and prepared by combining COFs-functionalized HF with 1-octanol,which can be directly separated from the sample solution after extraction,without the need for centrifugation,magnetic force and other auxiliary means.The operation was simple and fast.The consumption of extractant was small and it was protected in HF.Compared with the effects of three COFs(Tp-NDA,TPBD,DQTP)on the enrichment and extraction of BPs,COF@Tp-NDA with the best response to BPs was selected,which had good stability in acid solution,alkali solution and organic solution.The peak areas of BPs extracted by HF@COF@Tp-NDA extraction bar were 6.96～10.82 times that of bare HF.Under the optimal experimental conditions,the developed method obtained great linear range(R~2≥0.9974)in the range of 5～1000 ng/m L,limits of detection(0.10～2.00 ng/m L)and limits of quantification(0.40～5.00 ng/m L).The method was applied to the enrichment and determination of BPs in three beverages of tea,juice and milk.The results showed that bisphenol B was detected in tea,and the amount was 14.57 ng/m L,and the recoveries were 70.1%～106.8%.(2)The in-situ growth extraction fiber was designed to achieve rapid and efficient enrichment of BPs in complex matrix samples via electric drive,membrane protection and SPME synergy.The enrichment and extraction of BPs by the prepared SPME fibers were2.88～10.51 times,3.63～16.74 times and 1.44～5.09 times that of bare SSW and two commercial fibers(PDMS and PDMS/DVB),respectively.The rapid extraction of BPs was realized by electric drive,which was shortened from 25 min to 10 min.In addition,the SPME fiber was protected by membrane during the extraction process,which improved the reusability of the fiber.After 100 times of repeated use,the extraction efficiency was only 0.74%～5.10%lower than that of the first time;in the absence of membrane protection,the extraction efficiency of the fiber after 20 times of use was 31.06%～52.20%lower than that of the first time.Under the optimal experimental conditions,and the linear ranges of BPs were 2～600 ng/m L for BPAF and2～800 ng/m L for other BPs,and the limits of detection were 0.09～0.41 ng/m L,which met the detection of trace BPs in complex food.The developed method was applied to the enrichment and detection of BPs in three kinds of canned meat(pork,beef and fish).The detection amount of bisphenol AF in canned pork was 0.20μg/g,and the detection amount of bisphenol Z in canned pork and canned beef were 0.48μg/g and 0.65μg/g,the recoveries were 72.6%～116.9%. |
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