Preparation Of Molecularly Imprinted Monolithic Column And Their Application In The Monitoring Of Trace Ochratoxin A

Ochratoxin A(OTA)is one of the mycotoxins that produce a strong threat to the health of humans and animals.The research of the specific recognition of OTA in complex samples has great academic and practical significance.As a technique with specific binding ability,molecular imprinting combines with the monolithic column to form a molecularly imprinted monolithic column with the advantages of good specificity,strong stability,large binding capacity and reusability.In this paper,OTA was used as the template molecule,and2-acrylamide-2-methylpropanesulfonic acid(AMPS)was creatively used as the functional monomer to prepare a novel organic-inorganic hybrid molecularly imprinted monolithic column,via using a simple,efficient and fast “one-pot” combined with thermal initiation or photoinitiation.And its specific recognition ability and chromatographic performance were evaluated.The main research contents are as follows:In chapter 1,literature review.The origin,toxicity,pollution and limit standards of OTA were introduced and the current methods of OTA detection,sample pretreatment and types of solid phase extraction adsorbent were summarized.Based on these statements,the significance and research scheme of this thesis were proposed.In chapter 2,a novel molecularly imprinted microextraction hybrid monolithic column was synthesized with “one-pot” process via free radical polymerization using OTA as the template molecule,AMPS as the functional monomer,methacrylate-substituted polyhedral oligomeric silsesquioxane(POSS-MA)and ethylene glycol dimethacrylate(EDMA)as the cross-linker.The preparation conditions of the monolithic column were optimized.The morphology,specific recognition ability,binding capacity and stability of the monolithic column were investigated.The interaction mechanisms between the monolithic column and the target analyte were explored.The results show that the prepared monolithic column has a better specific recognition ability for OTA.In the presence of competitive distracter OTB with different concentrations,the recoveries of OTA were between 81.8 ～ 83.4%,and the recoveries of OTB were always below 3.3%.In chapter 3,to solve the problems such as time-consuming preparation and low reaction efficiency in the common thermal initiated polymerization,a novel aptamer-molecular imprinting(Apt-MIP)double-recognition hybrid monolithic column was prepared in 7 min by photoinitiated free radical polymerization and “thiol-ene” click chemical reaction introduced aptamer in the monolithic column.The monolithic column further improved the specific recognition ability for OTA by using the double recognition of molecular imprinting and aptamer.The effects of photoinitiation time,amount of photoinitiator,and concentration of aptamer on the preparation of monolithic column were investigated.The prepared photo-initiated Apt-MIP hybrid monolithic column has a relatively uniform skeleton structure,and better specific recognition ability for OTA.Moreover,in mixture samples with OTA and OTB concentration ratios of 1:1 and 1:10,the recoveries of OTA were over 88.3%,while the recoveries of OTB remained below 2.9%.When applied to the high specific enrichment,separation and detection of OTA in actual beer samples,the recoveries of OTA were 95.5 ± 1.6% ～ 105.9 ± 1.7%(n = 3).