Application Of Crygels In Sample Pretreatment

Monolith is an important material in many field,which is used simply and easy to carry and operate.Sample pretreatment is the key step in analytical chemistry,which determines the final result and conclusion.Wrong result or conclusion will affect the decision,the policy and the diagnose and further affect the health and environment.In the thesis,we improve the cryogel preparation method and modified kinds of groups in basic cryogel to pretreat samples.We tried to avoid the use of organic solvents and to decrease the pollution to body and environment,and propose to the green chemistry idea.Four parts are included:First,the history,synthesis method,advantage and shortage of cryogel were introduced.Second,a green and promising sample pretreatment method was successfully established,which efficiently isolated proteins and small molecules in human serum.This method was achieved based on the multifunctional cryogel?pDC/GO-DE?as a solid phase extraction?SPE?monolith easily equipped in a syringe.The cryogel was composed of diallyldimethyl ammonium chloride?DC?and 2-hydroxyethyl methacrylate?HE?,which was further modified with graphene oxide?GO?and N-diethylethanamine hydrobromide?DE?.Various proteins,including bovine serum albumin?BSA?,lysozyme?Lys?,?-globulins,immunoglobulin G?IgG?,transferrin,small molecules?ribavirin,adenosine,ofloxacin,estriol,rutin,amoxicillin,ibuprofen,1-methyl-3-phenyl-propylamine,and benzylamine?and their mixtures were successively studied as model analytes to evaluate the new material and demonstrate the isolation mechanism,which was mainly dependent on mixed-mode ion-exchange and the hybrid hydrophobicity-hydrophilicity property of pDC/GO-DE cryogel.Moreover,the three-dimensional macroporous structure contributed to the underlying size-selective isolation.When 10 times diluted human serum was used as the sample,more than 95%of proteins were adsorbed within 10 min under physiological conditions,and the interference matrix in serum was also efficiently reduced.After recycling three times,the extraction ratio of proteins in human serum was still higher than 90%.When four small molecules?camptothecin,ribavirin,1-methyl-3-phenylpropylamine and ofloxacin?were added to blank human serum,their recoveries were within 65.6–81.8%,which were comparable to those obtained by protein precipitation method?63.7–83.2%?.Third,we tried to synthesize cryogels for adsorption of nucleosides.Two parts were included:?1?A simple synthesis procedure was used to copolymerize 2-vinylbenzeneboronic acid into the cryogel,which was used for adsorption of nucleosides.The cryogel has the very high adsorption capacity,higher than most reported.We used the cryogel as extaction adsorbent to determine the nucleosides in diluted serum and three nucleosides were quanlified.The shortage of the material is the desorption is difficult when too much nucleosides were adsorbed on it.?2?A versatile platform based on the well-organized cryogel composites with abundant porous structure was presented,which was achieved by in situ copolymerization of mesoporous silica(MSi_NBC)and monomers?HE and DC?in water below the freeze point.The mesoporous silica(MSi_NBC)was prepared and tailored with amine,boronic acid and methacrylate groups.The pores on the pMSi_NBC provided sufficient reactive sites and were favorable for efficient mass transport for target compounds.When the pMSi _NBC was used as SPE adsorbent and further coupling to high performance liquid chromatography as analytical tool,the nucleosides were quantified with good selectivity,lower limits of detection?0.9-1.3 ng/mL?and satisfied recoveries higher than 80%from spiked human serum.Fourth,enzymes have been considered as an important green catalyst for industrial manufacture.A new enzyme reactor was presented for providing good biocompatible microenvironment to protect the original tertiary structure of enzymes and improve their catalytic performance,which was based on the 3D porous cryogel composite of pDM/p/Au,in which DC was employed as the crosslinker and flowerlike metal-organic frameworks?MOFs?as monomer,rapidly generating polydopamine film?p?and well-proportioned nanogold?Au?biomimetic interface.The pDM/p/Au cryogel with high mechanical stability was fabricated by a scale and ecofriendly semi-automation preparation strategy.All the operations were carried out under mild reaction conditions,in aqueous solution and without repeated drying.Trypsin?T?was chosen as the model enzyme to immobilize by the nanogold as the intermediate ligand,the immobilized trypsin on pDM/p/Au?pDM/p/Au-T?exhibited efficient immobilization time?t=1 h?,wide catalytic temperature?25⁶5°C?and pH?6¹0?range,good reusability?reusing 8 times?and storage stability?4 weeks,retained higher than 80%residual activity?.Its catalytic performance also demonstrated by protein digestion with BSA as model protein and the digestion time was 1min.