The Application Of Metal-organic Frameworks Hybrid Material In Solid-phase Extraction In Food

Metal-organic frameworks(MOFs)are a kind of new multi-functional porous materials composed of metal and organic ligands,which have many advantages such as large specific surface area and pore size adjustable and easy to modify after modification.Therefore,MOFs has attracted much attention in the pretreatment technology of sample.This paper aims to explore the application potential of MOFs as adsorbents in the safety of food and water.The main research contents and innovations are summarized as follows:1.Utilization of UiO-66-NH₂@cellulose hybrid aerogel for solid-phase extraction of sildenafil in health productsA new method for the determination of sildenafil by solid phase extraction(SPE)and high performance liquid chromatography(HPLC)using UiO-66-NH₂@cellulose aerogel as adsorbent was proposed.The functionalized cellulose with aldehyde and hydrazide groups was crosslinked and loaded with UiO-66-NH₂to form a hybrid aerogel.The hybrid aerogel used as the adsorbent of solid-phase extraction,easy to collect and does not require additional magnetic field or vacuum auxiliary function,simple operation.From pH,extraction time,the type of eluant,the times of elution and elution time and salinity to optimize experimental conditions.The analysis method is verified through the analysis of real samples of feasibility and applicability.The results showed that UiO-66-NH₂@cellulose aerogel had a good enrichment effect on sildenafil,a wide linear range(10-2000ng/mL),a low detection limit(2.85 ng/mL)and a high recovery(74.93%-89.12%).2.Fe/Co-C magnetic materials were used for magnetic solid phase extraction of four pesticidesFe/Co-C materials with magnetic properties were prepared by calcination with Fe/Co-MOF as precursors.Four pesticides(Atrazine,pyrazole,azolamide,diphenylthrin)were determined by magnetic solid phase extraction and high performance liquid chromatography(HPLC)with Fe/Co-C as adsorbent.The effects of pH,extraction time,the type of eluent,the time of elution,the times of elutionand salinity on enrichment were investigated.The results showed that Fe/Co-C magnetic materials had good enrichment effects on the four pesticides.In the range of 1-500,10-500,2.5-500 ng/mL,the chromatographic peak area of atrazine,ppyrazole,azole amide and biphentirin after extraction was proportional to the concentration of the four pesticides.The method was applied to the extraction of surface water samples and jasmine flowers,and the recoveries were71.32%-87.37%with RSD of 1.06%?4.59%,indicating that the method has good recovery and precision.And it also illustrates that the method has the potential to be applied to the daily detection of pesticides.3.Fe/Co-MOF@Fe₃O₄nanoflow for magnetic solid phase extraction of estrogenA new method for the determination of estradiol and estradiol by magnetic solid phase extraction(MSPE)with Fe/Co-MOF@Fe₃O₄nanoflow as adsorbent was proposed.Firstly,Fe₃O₄nanoflowers were prepared by calcination method,and then Fe/Co-MOF was grown on the surface of Fe₃O₄nanoflowers to form Fe/Co-MOF@Fe₃O₄nanoflowers hybrid material.The effects of pH,the time of extraction,the type of eluent,the time of elution,the times of elution and salinity on the enrichment effect were investigated.The results showed that Fe/Co-MOF@Fe₃O₄nanoflow had a good enrichment effect on two kinds of estrogen,estrone and estradiol were in the range of 1-1000 ng/mL,the chromatographic peak area after extraction was proportional to the concentration.The method was applied to the actual sample detection,the recovery rate was58.07%?72.56%,with RSD of 2.58%?4.01%,indicating that the method has good recovery and precision.And it also illustrate that the method has potential application...