Application Of Ionic Liquid Modified Magnetic Zeolitic Imidazolate Frameworks In The Analysis Of Microcystins And Aflatoxins

Microcystins?MCs?and aflatoxins?AFs?are two pollutants colsely related to human life.Both of them are listed in the list of carcinogens published by the International Agency for Research on Cancer of the World Health Organization.They involve two major issues of human drinking water and food safety.Therefore,there is very important and realistic significance for the determination of MCs in water samples and AFs in food samples.Magnetic solid phase extraction?MSPE?is a new pretreatment technology appearing in the21st century.It has became a pretreatment method with very high extraction capacity and efficiency.The continuous innovation of new MSPE adsorbents promotes the rapid development of MSPE.Ionic Liquid modified magnetic zeolite imidazole ester matrix composite is a new adsorbent with convenient magnetic separation and high adsorption efficiency.It has good application porspects.In this paper,a MSPE method was developed based on the new adsorbent,and was tested by high performance liquid chromatography tandem mass spectrometry?HPLC-MS/MS?.The studies of this paper is mainly about:?1?Fe₃O₄ magnetic particles were prepared by hydrothermal method,magnetic zeolite imidazole ester matrix material?M/ZIF-8?was prepared by water bath method,ionic liquid modified magnetic zeolite imidazole ester matrix material?IL@M/ZIF-8?was prepared by acetone evaporation loading method,and its properties were characterized by SEM,TEM,FT-IR,specific surface area,pore size and magnetic strength.The results showed that ionic liquids?IL?and zeolite imidazole skeleton?ZIF-8?were successfully loaded on the surface of Fe₃O₄,and the IL@M/ZIF-8 adsorbent had larger specific surface area,pore size and magnetic strength.?2?IL@M/ZIF-8 of MSPE-HPLC-MS/MS method has been developed for the determination of two MCs in water samples.The adsorption conditions of MSPE were optimized,and the optimized conditions about this method were:50mg of IL@M/ZIF-8,extraction time of 20min,water sample pH of 3,desorption solvent of acetonitrile-0.1%formic acid aqueous solution?9:1,v/v?,desorption solvent volume of 3000?L.Under the optimum conditions,the detection limits were 0.02⁰.04?g/L,the recoveries of actual water samples were 88.5¹08.3%and the relative standard deviations were 1.5⁷.2%.?3?IL@M/ZIF-8 of MSPE-HPLC-MS/MS method has been developed for the determination of four AFs in milk samples.The adsorption conditions of MSPE were optimized,and the optimized conditions about this method were:90mg of IL@M/ZIF-8,extraction time of 15min,water sample pH of 8,desorption solvent of ACN?DCM?1?1,v/v?,desorption 2 times and 1000?L for each time,sample solution volume of 20mL.Under the optimum conditions,the detection limits were 0.02⁰.40?g/L,the recoveries of actual water samples were 79.0¹02.5%and the relative standard deviations were 2.5⁷.4%.