本文關(guān)鍵詞： 三聚氰胺 分子印跡聚合物 計算模擬 功能單體 交聯(lián)劑 溶劑　出處：《吉林農(nóng)業(yè)大學(xué)》2016年碩士論文　論文類型：學(xué)位論文

【摘要】：三聚氰胺(Melamine,MAM)是一種高含氮量的有機化工原料,主要用于生產(chǎn)膠黏劑、膠水、層壓板等。其加入到食品中可提高蛋白質(zhì)的表觀含量,對人類健康造成嚴重威脅。近幾年,發(fā)生在國內(nèi)外嬰兒奶粉受MAM污染導(dǎo)致腎結(jié)石事件使MAM的檢測成為研究的熱點。因此,如何從食品中快速、準確且低成本地分離、純化MAM目標待測物,對提高其檢驗方法的靈敏度及準確度具有重要的意義。分子印跡技術(shù)是以某一特定的目標分子為模板(印跡)分子,制備對該分子有特異選擇性識別的分子印跡聚合物(Molecularly imprinted polymers,MIPs)的過程。MIPs具有較好的理化穩(wěn)定性、構(gòu)效預(yù)定性和特異識別性,在固相萃取、色譜分離、傳感器、催化劑等諸多領(lǐng)域展現(xiàn)了良好的應(yīng)用前景。其制備受功能單體、印跡反應(yīng)比例、溶劑及交聯(lián)劑等諸多因素的影響,為提高MIPs對印跡分子的親和性、選擇性和識別性,計算機輔助模擬被廣泛地應(yīng)用于優(yōu)化分子印跡體系。本研究借助Gaussian 09軟件,分別選用B3LYP、PBE1PBE、LC-wPBE和WB97XD四種密度泛函理論方法與兩種基組(6-31G(d,p)、6-31+G(d,p))優(yōu)化MAM印跡分子。結(jié)果表明,WB97XD/6-31G(d,p)方法更適合三聚氰胺分子印跡聚合物(MAM-MIPs)的理論研究。然后以WB97XD/6-31G(d,p)為計算方法,MAM為印跡分子,丙烯酰胺(Acrylamide,AM)、甲基丙烯酸(Methacrylic acid,MAA)、N,N-亞甲基雙丙烯酰胺(N,N'-Methylenebisacrylamide,MBA)、衣康酸(Itaconic acid,IA)及三氟甲基丙烯酸(Trifluoromethylacrylic acid,TFMAA)為功能單體,二乙烯基苯(Divinylbenzene,DVB)、乙二醇雙甲基丙烯酸酯(Ethylene Glycol Dimethacrylate,EGDMA)、三羥甲基丙烷三甲基丙烯酸酯(Trimethylolpropane Trimethylacrylate,TRIM)和季戊四醇三丙烯酸酯(Pentaerythritol triacrylate,PETA)為交聯(lián)劑,模擬并探討MAM與五種功能單體間的成鍵作用位點、成鍵數(shù)目、印跡反應(yīng)摩爾比例及印跡作用機理,依據(jù)結(jié)合能(△E)優(yōu)化功能單體和交聯(lián)劑,溶劑化能篩選印跡體系的最佳溶劑,并借助分子中的原子理論(Atoms In Molecules,AIM)與紅外光譜揭示MAM與功能單體印跡作用的本質(zhì)。計算結(jié)果表明:MAM通過氫鍵與功能單體進行印跡聚合,其中IA作為功能單體與印跡分子形成的復(fù)合物結(jié)合能最低,結(jié)構(gòu)最穩(wěn)定,且最佳反應(yīng)摩爾比例為1:6;DVB與MAM結(jié)合能最低,更適合作為MAM-MIPs的交聯(lián)劑。在甲醇(Methanol,MT)溶劑中有望合成對MAM印跡分子識別與選擇能力較強的MIPs。在MAM-MIPs穩(wěn)定復(fù)合物構(gòu)型的基礎(chǔ)上去除印跡分子MAM,并固定剩余原子,在對應(yīng)位置分別插入MAM結(jié)構(gòu)類似物環(huán)丙氨嗪(Cyromazine,CYR)、三聚氰酸(Cyanuric acid,CYA)、三聚硫氰酸(Trithiocyanuric,TRI)分子作為底物,通過再結(jié)合能來預(yù)測MIPs對MAM的親和性和選擇性。結(jié)果表明,MAM-MIPs對MAM印跡分子展現(xiàn)出良好的選擇吸附性。依據(jù)理論計算結(jié)果,采用沉淀聚合法合成一系列不同功能單體、交聯(lián)劑、印跡摩爾比例、溶劑的MAM-MIPs,測定其吸附量并進行表征。實驗結(jié)果表明,與AM、MAA、MBA、TFMAA相比,IA作為功能單體,且印跡摩爾比例為1:6時形成的MAM-MIPs復(fù)合物結(jié)合能最低,結(jié)構(gòu)最穩(wěn)定;與EGDMA、TRIM、PETA交聯(lián)劑相比,DVB與MAM結(jié)合能最低,更適合作為MAM-IA印跡聚合物的交聯(lián)劑。在MT溶劑中制得的MAM-MIPs納米微球形貌較好,呈規(guī)則的球形,平均粒徑為195 nm。Scatchard分析結(jié)果表明,在研究濃度范圍內(nèi)MIPs對印跡分子MAM的結(jié)合位點是等價的,其最大表觀吸附量Qmax為20.79 mg/g,離解平衡常數(shù)Kd為58.82 mg/L;與CYR、CYA、TRI的吸附量相比,MAM-MIPs對MAM表現(xiàn)出較強的特異吸附能力。最后,在純牛奶樣品中添加一定量的MAM,將本研究所制得的MAM-MIPs作為吸附材料對奶制品中的MAM進行富集分離,其回收率高達99.41%。本研究為MAM-MIPs作為分離吸附劑選擇性分離和檢測奶制品中的MAM提供了依據(jù)。
[Abstract]:Melamine (Melamine, MAM) is a kind of high nitrogen content of organic chemical raw materials, mainly used in the production of adhesive, glue, laminated plate. It is added to food can increase the apparent protein content, poses a serious threat to human health. In recent years, in the domestic and foreign infant formula contaminated by MAM lead the kidney stone event has become a research hotspot of MAM detection. Therefore, how to quickly and accurately from the food, low cost, separation, purification of MAM target, to improve the test sensitivity and has important significance for accuracy. Molecular imprinting technique is based on a specific target molecule (imprinted as template) molecules, preparation of molecularly imprinted polymer specific and selective recognition of the molecule (Molecularly imprinted, polymers, MIPs) of.MIPs has good physical and chemical stability, structure-activity and predetermined specificity, in solid phase extraction, color Spectrum separation, sensor, catalyst and other fields show a good application prospect. The prepared functional monomer, blotting ratio, solvent effects of crosslinking agent and other factors, in order to improve the MIPs of molecular imprinting affinity, selectivity and recognition, computer aided simulation is widely applied to the optimization of molecular imprinting system this study with Gaussian 09 software, respectively by B3LYP, PBE1PBE, LC-wPBE and WB97XD four kinds of density functional theory and two kinds of basis set (6-31G (D, P), 6-31+G (D, P) MAM) to optimize the imprinted molecule. The results showed that WB97XD/6-31G (D, P) method is more suitable for melamine molecularly imprinted polymer (MAM-MIPs) theory. Then based on the WB97XD/6-31G (D, P) for the calculation method of MAM as the template molecule, acrylamide (Acrylamide, AM), methacrylic acid (Methacrylic acid, MAA), N, N- methylenebisacrylamide (N, N'-Methylenebisacrylamide, MBA Itaconic acid (Itaconic), acid, IA) and three fluorine (Trifluoromethylacrylic acid, TFMAA methacrylate) as functional monomers, two vinyl benzene (Divinylbenzene, DVB), ethylene glycol dimethacrylate (Ethylene Glycol, Dimethacrylate, EGDMA), three hydroxymethyl propane three methyl acrylate (Trimethylolpropane Trimethylacrylate, TRIM) and pentaerythritol three acrylate (Pentaerythritol triacrylate, PETA) as crosslinking agent, and to explore the role of key sites of MAM simulation and five kinds of functional monomer into the bonding reaction and the molar ratio of the number of Western blot mechanism, on the basis of energy (E) optimization of functional monomer and crosslinker and solvation energy is the best solvent screening imprinting system, and using the theory of atoms in molecules (Atoms, In Molecules, AIM) and infrared spectra revealed that the MAM and functional monomer for imprinting nature. The calculation results show that the MAM by hydrogen bonding and power Can the monomer imprinting polymerization which complex formation of IA monomer and imprinted molecules as a function of the binding energy of the lowest, the most stable structure, and the optimum molar ratio of 1:6; DVB and MAM with the lowest, more suitable as a crosslinking agent in methanol. MAM-MIPs (Methanol, MT) solvent to synthesis of MAM imprinted molecule identification and selection ability of MIPs. based on MAM-MIPs stable complex configuration on the removal of imprinted molecule MAM, and fixed the remaining atoms, are respectively inserted into the corresponding position in the MAM structural analogs of cyromazine (Cyromazine, CYR), cyanuric acid (Cyanuric, acid, CYA, Trithiocyanuric acid (Trithiocyanuric). TRI) molecules as substrate, to predict the MIPs of MAM affinity and selectivity by binding energy. The results showed that MAM-MIPs of MAM imprinted molecules show selective adsorption well. According to the theoretical calculation results, synthesized by precipitation polymerization 緋誨垪涓嶅悓鍔熻兘鍗曚綋,浜よ仈鍓，

本文編號：1498179