Construction Of A New Magnetic Covalent Organic Framework Material TAPB-BTT And Its Application In The Detection Of Ultraviolet Absorbents

Objective:Ultraviolet（UV）absorbents,as common additives in plastic packaging materials,may cause damage to human health,so the development of rapid,simple and environmentally friendly analytical methods is indispensable to ensure food and drug safety.In this study,seven kinds of UV absorbents were selected.According to their structural characteristics,a novel sorbent material was synthesized and applied to magnetic solid phase extraction（MSPE）.Using liquid chromatography combined with mass spectrometry,seven kinds of UV absorbents quantitative analysis methods were established and applied to actual sample determination.The aim of this study is to develop a novel analytical method for UV absorbents and provide technical support for food and drug safety.Methods:1.A magnetic covalent organic framework material（M-COF）of imine type was prepared by a simple and rapid co-precipitation method.The M-COF was analyzed and its synthesis verified by a series of characterization tools（scanning electron microscope,transmission electron microscope,Fourier transform infrared spectroscopy,X-ray diffraction analysis,thermogravimetric analysis,magnetic analysis and nitrogen adsorption-desorption experiments）.2.The M-COF was used as an adsorbent for MSPE and the extraction conditions of seven kinds of UV absorbents were optimized by single-factor experiments.The adsorption performance of the material was then investigated.3.The detection methods for seven kinds of UV absorbents was developed on ultra-high performance liquid chromatography-tandem mass spectrometry（UHPLC-MS/MS）and the liquid-mass conditions were optimized.The feasibility of the method was verified.Results:1.The designed and synthesized M-COF material（Fe₃O₄@TAPB-BTT）had a large specific surface area（876.3 m²/g）,large pore size and large conjugated network structure with good thermal stability and retained good magnetic properties,and could be used as an adsorbent material for sample pretreatment.2.Under the optimized MSPE conditions（4 mg of sorbent was used for 3 min at p H 7 followed by 2 min desorption using 2 m L acetonitrile）,satisfactory recoveries（76.9-95.6%）were obtained.3.The linear ranges of the seven UV absorbents were 0.001-100μg/L with determination coefficient（R²）>0.9985.After analyzing by UHPLC-MS/MS,the LODs and LOQs were0.001-0.15μg/L and 0.005-0.50μg/L,respectively,with intra-day and inter-day precision of 1.1-7.2%and 1.5-9.8%,respectively,in addition to negligible matrix effects（-11.5-5.2%）.Conclusion:1.The novel M-COF material Fe₃O₄@TAPB-BTT synthesized in this study had excellent adsorption performance on seven kinds of UV absorbents due to its good physicochemical properties.2.Combined with UHPLC-MS/MS analysis,the method showed a wide linear range,high sensitivity,high accuracy and good precision in the determination of seven kinds of UV absorbents.