Synthesis Of Porous Absorbent Material And Its Application In Food Inspection

In recent years,animal-derived food safety issues have frequently occurred.Some companies have chosen to abuse veterinary drugs and illegally add veterinary drugs in order to make profits once and for all,resulting in excessive veterinary drug residues.Sulfonamide antibiotics（SAs）are synthetic antibiotics.Due to their broad antibacterial spectrum,low price,and stable chemical properties,they are widely used in animal husbandry.SAs will continue to accumulate because they cannot be metabolized in the body,causing leukopenia,urinary system diseases and other diseases.Therefore,it is very important to detect veterinary drug residues quickly and accurately.However,due to the complexity of the sample matrix,the adsorption of impurities and the purification of the substance to be tested in the sample pretreatment process are very important.After consulting the literature,the hydrophilic-hydrophobic balanced filler（HLB）is widely used as a solid phase extraction filler.As a transition metal,metal Zr has an empty d orbital and can adsorb esters,but has a small specific surface area and a small loading capacity.Increase its specific surface area.Therefore,this work aims to develop three materials and apply them to sample pretreatment.In this thesis,HLB,UiO-66,and hierarchical porous ZrO₂ were sequentially synthesized as adsorption materials.The following are the four main contents of this paper:Introduction:First,it introduces the classification of veterinary drugs,the hazards of veterinary drug residues,and common sample pretreatment methods and detection methods.Then the porous materials are introduced,mainly including classification,synthesis methods,and applications.Secondly,the metal-organic framework is introduced,mainly introducing its characteristics,applications,classification,and synthesis methods.Finally,through the introduction of the previous article,the work carried out on this topic is introduced,and the meaning and ideas of the paper design are written.Part 1:The synthesis of hydrophilic-hydrophobic balance fillers and the application of SAs detection in foods.By optimizing the synthesis conditions,HLB materials were prepared and used in solid phase extraction to detect SAs.The optimization of the conditions showed that 1.5%of the dispersant PVA,0.6%of the coupling agent AIBN,70°C reflux temperature,and 200 r/min stirring speed were the most favorable conditions.And the material was characterized.In order to explore the influence of impurities（proteins,esters,etc.）in the sample matrix on the detection of SAs,the fluorescence quenching phenomenon of fish protein-SAs was explored,and the quenching binding constant K_B>10⁴ L/mol was calculated,which proved that fish protein.The strong interaction of SAs will affect the detection of SAs.The synthesized HLB was applied to the detection of actual samples,and the accuracy was spiked and recovered.The test results showed that the recovery rate was within80.1%～99.7%when the standard addition amount was 1 ppm,the detection limit was within 6.3～3.7μg/L,and the RSD was less than 2.86%,and the results were satisfactory.Compared with similar adsorbents PSA andOasis HLB,the results are also satisfactory.Therefore,the HLB synthesized in this work can be used as SPE material for sample pretreatment.Part 2:The synthesis of UiO-66 and the application of SAs in food.Due to the shortcomings of ZrO₂,such as small specific surface area,it is not suitable for adsorbents.Therefore,this work is based on the synthesis of Zr-based metal-organic framework UiO-66,and the material A series of characterizations including SEM,XRD,FT-IR,BET and TG were performed.In order to explore the adsorption effect of UiO-66 on the impurities（lipids）in the sample matrix,the adsorption conditions were optimized.The optimization results showed that the maximum adsorption capacity was 6.25g/g at p H=5.0 and 120 min adsorption time.The samples were applied to the actual sample detection,and the SAs in chicken were spiked and recovered.When the spiked amount was 1 ppm,the recoveries were all within 78.9%～91.2%,and the detection limit was within 17.6～3.8μg/L.Satisfactory results have been obtained.The results prove that UiO-66 can also be used as an adsorbent for impurities in the detection of animal-derived foods.Part 3:The synthesis of multi-porous ZrO₂and its application in the detection of SAs in food.In Part 2,UiO-66 cannot be used as SPE material.The possible reason is:even if the specific surface area is large,the food matrix contains a large amount of macromolecular substances,which cannot pass through the mesopores,causing the blockage of the SPE column.Therefore,in this work,a hierarchical porous ZrO₂ containing both mesopores and macropores was synthesized.The optimal reaction conditions were as follows:0.1 mmol P123（0.58 g）、2 mmol tannin（0.78 g）、0.5 mol Zr（SO₄）₂（1.775 g）and the material was characterized by SEM,XRD,FT-IR,and BET.In order to explore the adsorption effect of ZrO₂ on the impurities（lipids）in the sample matrix,the adsorption conditions were optimized.The optimization results showed that it was weakly acidic and reached the maximum adsorption capacity of 2.92 g/g at 60 min adsorption time.The samples were applied to the actual sample detection,and the SAs in chicken were spiked and recovered.When the spiked amount was 1 ppm,the recoveries were all within 80.9%～97.6%,and the detection limit was within17.6～3.8μg/L.Satisfactory results have been obtained,and the results prove that ZrO₂ can also be used as a solid-phase extraction material for impurities in the detection of animal-derived foods.