石墨烯量子点在水溶液中对汞离子、碘离子和有机小分子的检测研究

发布时间：2018-05-17 20:17

本文选题：石墨烯量子点 + 荧光　；参考：《上海师范大学》2017年硕士论文

【摘要】：石墨烯量子点(GQDs)是一种只有一个原子层厚的二维碳材料,具有杰出的电子性能、机械性能和化学稳定性。与传统量子点相比,石墨烯量子点不仅具有突出的电子和光学优势,还具有毒性低、溶解度高、稳定性高、光致发光、表面积大等优点。因此,石墨烯量子点在荧光探针、光电设备、传感器、细胞成像、药物递送、太阳能电池等领域具有广阔的应用前景。目前,石墨烯量子点的研究主要集中在荧光传感器、生物成像和载药等方面。到目前为止,石墨烯量子点的制备方法主要有水热法、浓酸氧化法、溶剂热法、紫外-芬顿氧化法、电化学氧化法、有机分子合成法、微波辅助氧化法及化学剥离碳纤维法等。使用的碳源主要有氧化石墨烯、石墨棒、石墨薄膜、碳纳米管、碳纤维、炭黑、葡萄糖、柠檬酸以及树叶等。在本论文中,我们以碳纤维作为碳源,通过化学剥离碳纤维法制备出石墨烯量子点,然后在石墨烯量子点上修饰胸腺嘧啶,所得材料可用于检测汞离子,并可进一步用于碘离子和含巯基氨基酸的检测。该传感器具有灵敏度高、选择性好、操作方法简单、响应时间迅速等优点。本论文共包括以下四章。第一章综述了石墨烯量子点的制备方法、性质和应用,并根据石墨烯量子点的荧光性质设计了实验方案。第二章中,我们制备了胸腺嘧啶修饰的石墨烯量子点,并利用这种材料进行了汞离子、碘离子、含巯基氨基酸的检测实验。采用化学剥离碳纤维法制备出石墨烯量子点,再以乙二胺为连接剂通过酰胺键将胸腺嘧啶修饰到石墨烯量子点上,得到胸腺嘧啶修饰的石墨烯量子点。加入汞离子后,胸腺嘧啶修饰的石墨烯量子点对汞离子具有较高的灵敏度和较好的选择性,其对汞离子的检出限为211nM。此外,基于“T-Hg2+-T”结构,发展了一种简便的“turn on”型荧光探针。这种探针可以用来检测碘离子和含巯基的氨基酸(如半胱氨酸、谷胱甘肽和高半胱氨酸)。首先在材料中加入汞离子,由于“T-Hg2+-T”结构的生成,引起胸腺嘧啶修饰的石墨烯量子点发生团聚,导致荧光下降。若在此时,向溶液中加入碘离子,由于碘离子与汞配位生成更稳定的络合物,汞离子被竞争下来,“T-Hg2+-T”结构被打开,荧光得到恢复。这种荧光探针对碘离子的检出限为2.80μM。根据软硬酸碱理论(HSAB),汞离子与巯基之间有很强的结合能力,因此结合了汞离子的胸腺嘧啶修饰石墨烯量子点可以用于识别含巯基氨基酸。通过这种方法制备出的荧光探针对半胱氨酸、谷胱甘肽、高半胱氨酸的检出限分别为4.01μM、1.92μM、2.00μM。第三章中,我们研究了石墨烯量子点对三价铁离子和抗坏血酸的检测。由于石墨烯量子点上含有羟基、羧基等含氧官能团,三价铁离子与这些含氧官能团具有很好的亲和能力,引起石墨烯量子荧光强度下降。经过实验测定,石墨烯量子点对三价铁离子的检出限为5.7 nM。此外,抗坏血酸具有较强的还原性,三价铁离子具有较强的氧化性,二者之间可以发生氧化还原反应。此过程中,三价铁离子被还原为二价铁离子,导致三价铁离子与石墨烯量子点上的含氧官能团之间的配位被破坏,石墨烯量子点的荧光得到恢复。石墨烯量子点与三价铁离子的复合材料对抗坏血酸的检出限为536 nM。此种方法选择性好,灵敏度高。第四章根据本论文的实验数据进行总结,并对石墨烯量子点在光学领域的检测研究进行预测。
[Abstract]:Graphene quantum dots (GQDs) is a two-dimensional carbon material with only one layer thickness. It has outstanding electronic properties, mechanical properties and chemical stability. Compared with traditional quantum dots, graphene quantum dots not only have outstanding electronic and optical advantages, but also have low toxicity, high solubility, high stability, photoluminescence and large surface area. Therefore, graphene quantum dots have broad applications in the fields of fluorescent probes, photoelectric devices, sensors, cell imaging, drug delivery, solar cells and other fields. At present, the research of graphene quantum dots is mainly focused on fluorescence sensors, bioimaging and drug loading. So far, the preparation methods of graphene quantum dots are mainly There are hydrothermal methods, concentrated acid oxidation, solvent heat, ultraviolet Fenton oxidation, electrochemical oxidation, organic molecular synthesis, microwave assisted oxidation and chemical stripping carbon fiber. The main carbon sources used are graphene oxide, graphite rod, graphite film, carbon nanotube, carbon fiber, carbon black, glucose, citric acid and leaves. We use carbon fiber as carbon source to prepare graphene quantum dots by chemical stripping carbon fiber method, and then modify thymine on graphene quantum dots. The obtained materials can be used to detect mercury ions and can be used for the detection of iodide ions and sulfhydryl amino acids. The sensor has high sensitivity, good selectivity and simple operation method. The following four chapters are included in this paper. Chapter 1 summarizes the preparation methods, properties and applications of graphene quantum dots, and designs an experimental scheme based on the fluorescence properties of graphene quantum dots. In the second chapter, we prepared thymine modified stony quantum dots and used this material to carry out mercury ionization. A quantum dot of graphene was prepared by chemical stripping carbon fiber method, and then the thymine was modified to the graphene quantum dots with acetamide bond with acetamide as a connector. The graphene quantum dots modified by thymine after adding mercury ions was added to the quantum dots. With high sensitivity and selectivity for mercury ions, the detection limit for mercury ions is 211nM.. Based on the "T-Hg2+-T" structure, a simple "turn on" fluorescent probe has been developed. This probe can be used to detect iodide ions and amino acids containing sulfhydryl groups (such as cysteine, glutathione and homocysteine). With the addition of mercury ions in the material, due to the formation of the "T-Hg2+-T" structure, the graphene quantum dots modified by thymine resulted in the aggregation of graphene quantum dots, which resulted in the drop of fluorescence. If at this time, iodide ions were added to the solution and the iodide ions and mercury complexes formed a more stable complex. The mercury separation was competitive, the "T-Hg2+-T" structure was opened and fluorescence was opened. The detection limit of the fluorescence probe to iodine ion is 2.80 mu M. according to the theory of soft and hard acid base (HSAB), and there is a strong binding ability between the mercury ion and the sulfhydryl group. Therefore, the mercury ion's thymine modified Shi Moxi quantum dots can be used to identify the sulfhydryl amino acids. The detection limits of ammonia, glutathione, and homocysteine are 4.01 M, 1.92 M and 2 M. third. We studied the detection of ferric ion and ascorbic acid by graphene quantum dots. The intensity of graphene quantum fluorescence decreases. The detection limit of the graphene quantum dots on trivalent iron ions is 5.7 nM., the ascorbic acid has strong reducibility, the trivalent iron ions have strong oxidization and the redox reaction can occur between the two. In this process, the trivalent iron ions are reduced to two valence iron. Ions, which cause the coordination between the trivalent iron ions and the oxygen functional groups on the graphene quantum dots, is destroyed, the fluorescence of Shi Moxi quantum dots is restored. The detection limit of the composite material of graphene quantum dots and trivalent iron ions against bad blood acid is 536 nM., the selectivity is good and the sensitivity is high. The fourth chapter is based on the number of experiments in this paper. It is concluded that the detection of graphene quantum dots in optical field is forecasted.
【学位授予单位】：上海师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O657.3

【相似文献】