量子点分子印迹荧光传感器的设计及其对食品污染物选择性识别与检测的应用研究

发布时间：2018-06-14 01:00

本文选题：量子点 + 分子印迹　；参考：《江苏大学》2017年硕士论文

【摘要】：食品污染问题随着现代工业的发展变得日益严重,严重威胁了人类的身体健康,所以食品污染物的检测和监控显得尤为重要。然而传统的检测方法预处理较为复杂、步骤繁琐、耗时耗力,已经渐渐不能满足对食品污染物快速、简便、准确检测的需求。此外,食品种类繁多、成分复杂,需要检测的目标物通常含量较低,需要对待测物进行分离和富集。因此,开发出选择性好、识别快速、灵敏度高的新方法用于食品污染物的检测已刻不容缓。分子印迹荧光传感器结合分子印迹技术和荧光检测技术的优点,能够在复杂样品组分中准确识别并预富集痕量待检测物,基于分子印迹荧光传感器吸附富集待测物造成的荧光强弱变化达到目标物定量分析的效果。本文结合表面分子印迹技术和量子点荧光检测手段,以氧化石墨烯(GO)和多孔硅为基质材料,制备出形貌规整和能够特异性识别食品污染物的分子印迹荧光传感器。通过各种表征对制备的荧光传感器的微观结构和表面基团进行了分析,并探讨其对食品中微量污染物的识别能力和响应速度。另外,还通过常见食品的加标回收检测对荧光传感器的实用性进行了考察。主要研究内容和结果如下:(1)以Mn掺杂ZnS量子点/GO复合物为基质材料,以丙酰胺(PAM)为伪模板,甲基丙烯酸(MAA)为功能单体,制备了一种新型的表面印迹荧光传感器(AM-MIP)并用于检测油炸食品中的丙烯酰胺(AM)含量。通过表征手段对这种AM-MIP的结构和形貌进行分析,发现石墨烯表面形成一层均匀的印迹层。静态吸附实验表明AM-MIP对目标物的吸附到达平衡时间短,是一种能够快速识别丙烯酰胺的传感器。通过荧光检测实验,考察该传感器在不同pH条件下的稳定性、检测范围和荧光稳定性,发现制备的荧光传感器稳定性高且检测范围广。AM-MIP被进一步用于油炸食品中痕量AM的检测,验证了该荧光传感器的实用性。(2)通过溶胶-凝胶法在ZnO量子点表面进行SiO_2包覆,以三嵌段共聚物(P123)为致孔剂,合成一种稳定的SiO_2@ZnO多孔荧光基质材料。以三聚氰胺(MEL)为模板,丙烯酸(AA)为功能单体,制备了能够快速吸附MEL的分子印迹荧光传感器(MEL-MIP)。所合成的材料随后通过电镜、光谱表征分析其结构。考察了pH、样品浓度、吸附时间对其识别吸附能力的影响,结果表明其是一种稳定、响应快速的荧光传感器。通过荧光猝灭线性检测确定其有较低的检出限和宽的检测范围,并用于乳制品中痕量MEL的分析。(3)以SBA-15为微反应器,糠醇(FA)为碳源前驱体,在SBA-15内壁高温碳化形成石墨烯,通过高温高压硝酸蒸气进行氧化切割形成尺寸形貌规整的石墨烯量子点(GQDs)。以双酚A(BPA)为模板分子,甲基丙烯酸甲脂(MMA)和L-苯丙氨酸甲酯(MAP)为功能单体,在功能化后的GO表面进行聚合,在聚合过程中引入GQDs,制备了一种新型荧光表面分子印迹传感器(BPA-MIP)。在干扰实验中,发现合成的BPA-MIP能够选择性识别BPA且灵敏度高。在荧光响应实验中,发现其具有较宽的检出范围。加标回收实验检测饮料样品中BPA的含量发现其具有很好的回收率。(4)以柠檬酸胺和乙二胺为碳源前驱体,水热法合成了水溶性掺氮碳量子点(NCQDs)。MAA为功能单体,4-硝基苯酚(4-NP)为模板分子,在GO表面印迹聚合物骨架中掺杂NCQDs,制备了一种对4-NP有着特异性识别吸附的分子印迹荧光传感器(4-NP-MIP)。合成4-NP-MIP后用表征方法对其形貌和结构进行分析,发现其呈现均匀的印迹微球包覆在二维材料表面的结构。静态吸附实验研究其最佳吸附条件为pH=7.0,吸附到达平衡时间短,并对吸附参数进行分析和讨论。对市场上蔬菜样品加标分析,发现其具有高灵敏性和回收率。
[Abstract]:The problem of food pollution is becoming more and more serious with the development of modern industry, which seriously threatens the health of human beings. Therefore, the detection and monitoring of food contaminants is very important. However, the traditional method of preprocessing is complicated, and the steps are complicated and time-consuming. It has gradually been unable to meet the rapid, simple and accurate inspection of food contaminants. In addition, there are many kinds of food, complex ingredients, usually low content of objects to be detected and need to be separated and enriched. Therefore, a new method to detect food pollutants with good selectivity, fast recognition and high sensitivity is not slow. Molecular imprinting fluorescence sensor combined with molecular imprinting technology The advantages of the fluorescence detection technology can accurately identify and preconcentrate trace amounts in the complex sample components. The effect of fluorescence intensity changes caused by the adsorption of molecular imprinted fluorescence sensors to the quantitative analysis of the target objects is achieved. This paper combines the surface molecular trace technology and the quantum dot fluorescence detection method. Shi Moxi (GO) and porous silicon are used as matrix materials to prepare a molecularly imprinted fluorescence sensor that has a regular morphology and a specific identification of food contaminants. The microstructure and surface groups of the fluorescent sensors prepared by various characterization are analyzed, and the identification and response speed of trace contaminants in food are also discussed. The main research contents and results are as follows: (1) a new type of surface imprinted fluorescence sensor (AM-M) was prepared with Mn doped ZnS quantum dot /GO complex as matrix material, PAM as pseudo template and methacrylic acid (MAA) as power monomer. IP) was used to detect the content of acrylamide (AM) in fried foods. The structure and morphology of the AM-MIP were analyzed by means of characterization. A homogeneous layer of imprinting layer was found on the surface of graphene. The static adsorption experiment showed that the adsorption of AM-MIP on the target reached a short equilibrium time. It was a kind of fast sensor to identify the acrylamide. The stability, detection range and fluorescence stability of the sensor under different pH conditions were investigated by fluorescence detection experiments. It was found that the stability of the fluorescence sensor was high and the detection range was wide.AM-MIP was further used in the detection of trace AM in fried food. The practicability of the fluorescent sensor was verified. (2) through the sol-gel method in ZnO The quantum dot surface is coated with SiO_2, and a stable SiO_2@ZnO porous fluorescent matrix material is synthesized with three block copolymer (P123) as a pore agent. The molecular imprinting fluorescein sensor (MEL-MIP), which can quickly adsorb MEL, is prepared with melamine (MEL) as a template and acrylic acid (AA) as a functional monomer. The synthesized materials are followed by electron microscopy and light. The effect of pH, sample concentration and adsorption time on the identification of adsorption capacity was investigated. The results showed that it was a stable, fast response fluorescence sensor. By fluorescence quenching linear detection, it has a low detection limit and wide detection range, and is used for the analysis of trace MEL in dairy products. (3) SBA-15 is a micro scale. The reactor, furfuryl alcohol (FA) as a precursor of carbon source, carbonized a graphene at high temperature on the inner wall of SBA-15 and formed a structured graphene quantum dot (GQDs) by oxidation of high temperature and high pressure nitric vapor to form a structured graphene point (GQDs). With bisphenol A (BPA) as a template molecule, MMA and L- phenylalanine methyl ester (MAP) as functional monomers, after functionalization. A new fluorescent surface molecular imprinting sensor (BPA-MIP) was prepared by introducing GQDs into the GO surface. In the interference experiment, it was found that the synthesized BPA-MIP was able to identify BPA with high sensitivity. In the fluorescence response experiment, it was found that it had a wide detection range. The content of BPA was found to have good recovery. (4) using citric acid amine and ethylenediamine as the precursor of carbon source, water soluble nitrogen doped carbon quantum dots (NCQDs).MAA as functional monomers, 4- nitrophenol (4-NP) as template molecule, and NCQDs in the matrix of GO surface imprinted polymer were doped with NCQDs. A kind of specific identification adsorption on 4-NP was prepared. Molecular imprinting fluorescence sensor (4-NP-MIP). After synthesis of 4-NP-MIP, its morphology and structure were analyzed. It was found that the structure of the microspheres was coated on the surface of the two-dimensional material. The best adsorption condition was pH=7.0, the adsorption equilibrium time was short, and the adsorption parameters were analyzed and discussed. The analysis of vegetable samples in market shows that it has high sensitivity and recovery rate.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TS207.5;O657.3

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