【作者】 王艳玲；

【导师】 刘俊渤；

【作者基本信息】 吉林农业大学 ， 应用化学， 2014， 硕士

【摘要】 恩诺沙星（Enrofloxaoin，ENRO）作为第三代喹诺酮类药物，广泛应用于治疗动物和人类的多种感染性疾病。但随着该药物在兽医临床和动物养殖业中的违规使用，造成动物源性食品中ENRO残留现象极为严重，且其残留对人类健康产生了一定的危害。因而，从基体组成复杂的食品样品中准确地分离、纯化、富集ENRO待测物，提高其检测方法的准确度及灵敏度具有重要的意义。分子印迹材料是模拟自然界中的分子识别机制，将指定的印迹分子、功能单体与交联剂在的适当溶剂中聚合而制备得到具有特异吸附性的材料。近几年，被广泛应用作高效液相色谱法的在线预处理、固相萃取、食品安全监测及化学传感器等领域。采用静电纺丝技术制备恩诺沙星分子印迹纤维膜（Enrofloxacin molecularly imprinted nanofiber membranes，ENRO-MINFMs）既具有分子印迹聚合物（Molecularly imprinted polymers，MIPs）的特异性吸附能力又具有静电纺丝纤维膜的较大比表面积和较高孔隙率，可望提高ENRO分析检测的准确度与灵敏度。因此，本论文以ENRO为模板分子，采用沉淀聚合法和静电纺丝技术先后制备了ENRO-MIPs和ENRO-MINFMs，研究其印迹效应和识别性能。主要试验工作为：以ENRO为模板分子，甲基丙烯酸（MAA）为功能单体，采用量子化学密度泛函理论（DFT）的B3LYP/6-31G(d,p)方法，通过模拟ENRO与MAA的结合能，确定了模板分子与功能单体的最佳印迹比例为1:4。然后采用沉淀聚合法合成了MIPs微球，并对其MIPs进行电镜、红外、热重和吸附性等性能表征。结果表明，MIPs微球平均粒径（230nm）大于非印迹聚合物（NIPs）微球粒径（160nm），模板分子与功能单体之间存在氢键，且MIPs有较好的热稳定性；MIPs在吸附进行60min时基本达到饱和，Scatchard分析得Kd=465.116mg/L、Qmax=47.046mg/g，且吸附为放热过程；与结构相似的环丙沙星（CIP）和氧氟沙星（OFL）相比，MIPs对ENRO的吸附量明显高于CIP和OFL，表现出较高的特异性吸附能力，可以较好的应用于ENRO的分析检测。将沉淀聚合法制备的ENRO-MIPs微球添加到聚乙烯醇（PVA）溶液中，采用静电纺丝技术制备了ENRO-MINFMs。利用扫描电子显微镜（SEM）探讨了纺丝液浓度、纺丝电压及接收距离对MINFMs纤维直径及表面形貌的影响，从溶胀性、孔隙率、吸附容量及吸附选择性对印迹膜的性能进行了评价。结果表明，在环境温度25℃，相对湿度40%~50%，MIPs加入量8%，PVA质量分数7%，纺丝电压15kV，接收距离25cm的条件下得到的MINFMs的纤维形态良好，纤维平均直径为180nm。通过静电纺丝技术制备的MINFMs的溶胀度和孔隙率分别为136.76%、33.42%，均大于非印迹纳米纤维膜（NINFMs）；动力学吸附性能研究显示，MINFMs在300min后吸附基本达到平衡，且明显高于NINFMs的吸附量；Scatchard分析表明，在研究的浓度范围内MINFMs对模板ENRO的结合位点是等价的，其离解平衡常数（Kd）与最大表观结合量（Qmax）分别为Kd=505.817mg/L、Qmax=3.862mg/g。与环丙沙星（CIP）和氧氟沙星（OFL）相比，MINFMs对ENRO表现出更强的特异性吸附能力。在牛奶和鸡蛋的粗提液中添加不同量的ENRO，研究了MINFMs对这些样品中ENRO的回收率，其回收范围在80.21%-86.43%之间。本研究为ENRO-MINFMs的选择性分离、富集和检测复杂基质食品样品中的ENRO提供了依据。更多还原

【Abstract】 Enrofloxacin (ENRO), the third generation fluoroquinolones, has been widely used to treat avariety of animal and human infectious diseases. With its improper use in the veterinary clinic andanimal breeding industry, ENRO residues are likely to remain in the animal-derived food, and theirnegative effects are a big threat to human health. So, it is interesting to improve the sensitivity andthe specificity of the separation and enrichment from complex matrices.Enrofloxacin molecularly imprinted nanofiber membranes (ENRO-MINFMs) prepared byelectrospinning have both the specific adsorption capacity of the molecularly imprinted polymers(MIPs), and the large surface area and high porosity of electrospinning nanofibers, toovercome the deficiencies of the current detection technology. In this paper, we choose ENROas the template molecule to prepare the ENRO-MIPs and ENRO-MINFMs by the precipitationpolymerization and the electrospinning technique.The main contents are as follows:Enrofloxacin (ENRO) was taken as the template molecule and methacrylic acid (MAA) was takenas a functional monomer. The computational approach using quantum chemical density functionaltheory (DFT) at the B3LYP/6-31g(d,p) level were carried out to simulate the self-assembly systemof template and functional monomer. We optimized the molar ratio of ENRO and MAA bysimulating their binding energy and the optimum molar ratio of ENRO/MAA was1:4. Then, themicrospheres of the molecularly imprinted polymer (MIPs) were prepared by precipitationpolymerization using ENRO as template molecule and MAA as functional monomer. Wedetermined the optimum solvent and solvent usage via experiment. The MIPs were characterized.The results showed that MIPs microspheres were an average particle size of230nm, greater than thenon-imprinted polymeric microspheres (NIPs). Analysis of the Scatchard plot revealed that thebinding sites of MIPs to ENRO were equal class under the studied concentration range, and thedissociation constant (Kd) and apparent maximum binding capacity (Qmax) of MIPs were465.116mg/L and47.046mg/g, respectively. The adsorption quantity of MIPs to ENRO was obviouslyhigher than that of CIP and OFL, which showed better specific absorption capacity.Enrofloxacin (ENRO) molecular imprinted polymers (MIPs) obtained via precipitationpolymerization was added to the polyvinyl alcohol (PVA) aqueous solution. Then electrospinningtechnique was employed to prepare ENRO-MINFMs. We investigated the effects of concentrationof PVA solution, applied voltage, and the distance between the needle and collector on the diameter and morphology of the nanofiber membrane via scanning electron microscope (SEM) measurement.The swelling ratio, void ratio, adsorption property, and adsorption selectivity of membrane werealso studied. The optimal electrospinning process was carried out at environmental temperature of25℃and relative humidity of40%~50%, with PVA concentration of7.0wt%, spinning voltageof15kV, and the distance between the needle and collector of25cm. Under such conditions, thefibers in MINFMs were uniform with diameters of about180nm. The swelling rate and void ratioof the as-prepared MINFMs were136.76%and28.42%, respectively, which were more than thoseof non-imprinted nanofiber membranes (NINFMs). The dynamic adsorption experiments ofMINFMs showed that the adsorption reaction reached balance after300min. Analysis of theScatchard plot revealed that the binding sites of MINFMs to ENRO were equal class under thestudied concentration range, the dissociation constant (Kd) and apparent maximum adsorptionquantity (Qmax) of MINFMs were Kd=505.817mg/L and Qmax=3.862mg/g, respectively. Thespecific absorption capacity of MINFMs to ENRO was higher than those of ciprofloxacin (CIP) andofloxacin (OFL).Adding the different amounts of ENRO solution into the Milk and eggs, the recoveries of spikedsample were between80.21%and86.43%by MINFMs. It can be well applied to the actual testing.更多还原