荧光碳点的制备及其在叶酸和环丙沙星检测中的应用
发布时间：2019-06-09 23:05
【摘要】：碳点(Carbon dots,CDs)作为碳纳米材料家族的一名新成员,由于其具有独特的性质及潜在的应用价值,受到越来越多人的关注。相比于传统的有机染料和半导体量子点,碳点不但继承了碳纳米材料原料广泛、成本低的优点,还具有制备简单、易于修饰、发射波长可调谐、光稳定性好、毒性低和生物相容性好等优势,同时在光、电催化等方面也具有特殊的性质。因此,碳点在分析检测、催化、光电器件、生物传感以及生物医疗等领域呈现出广阔的应用前景。碳点的制备方法可以分为:自上而下法和自下而上法。自上而下法主要包括:超声法,激光消融法,电化学法等。自下而上法主要有:模板法,硝酸回流法,微波法,水热法等。本文从碳点的制备及其应用两个方面出发,寻找绿色环保的物质作为合成原料,探索碳点简便快捷的制备方法,并研究其在叶酸和环丙沙星检测中的应用。具体主要包括以下两个方面:(1)以乳糖为碳源,在NaOH强碱溶液环境中,通过水热法一步合成具有淡蓝色荧光的碳点。随后,对其进行以下表征:通过高分辨透射电子显微镜(HR-TEM)观察,碳点的分散性好,平均粒径约为2-3 nm;通过红外光谱表征,碳点表面含有 CH2、 CH3、 OH和 COOH等官能团。由于碳点能与叶酸特异性结合,因此我们以碳点作为荧光探针用于检测叶酸。其机理可能为:碳点表面的水溶性基团( OH和 COOH)和叶酸的亲水官能团( OH、 COOH和 NH2)相互作用,形成氢键,促使碳点发生聚集,从而导致荧光猝灭。通过条件优化,叶酸的浓度在6×10-5 mol/L-8×10-8 mol/L与碳点的荧光强度猝灭值呈线性相关,检测限为1.2×10-9mol/L。此外,该体系用于人体尿液样品中叶酸的检测,回收率在96.7%-103.0%之间,说明本文建立的荧光分析方法能成功用于实际样品中叶酸的检测。叶酸,又称维生素B9,是一种水溶性维生素,在人体的新生代谢扮演着重要的作用。一些疾病与叶酸的缺乏密切相关,例如:巨幼红细胞性贫血,中风,心脏病发作,精神病,婴儿畸形,癌症等。因此,开发方便快捷的分析方法用于检测叶酸,具有重要意义。(2)我们以羟丙纤维素(HPMC)作为碳源,通过水热法制备了发蓝色荧光的碳点。通过荧光光谱、高分辨透射电镜、紫外-可见吸收光谱、红外光谱、X射线光电子能谱等手段对其进行表征。碳点的粒径大小约为5.6 nm,荧光量子产率为1.36%;最大激发波长和最大发射波长分别为310 nm和420 nm,同时发现碳点具有发射波长依赖于激发波长的性质;通过结构表征,发现碳点表面富含-OH和-COOH等水溶性官能团。利用碳点表面基团能与环丙沙星结合,建立了检测环丙沙星的新方法。其线性范围在10 nM-90μM之间,检测限为5.88 nM(3σ),说明其检测范围较宽和灵敏度高,表明本文建立的荧光分析方法可以用于环丙沙星的检测。环丙沙星是第三代喹诺酮类广谱抗菌药,由于其对革兰性阳性菌和革兰性阴性菌都有良好的效果,导致其在生物体残留增多,所以对其痕量残留进行检测是一项很有意义的工作。
[Abstract]:Carbon dot (CDs), as a new member of the carbon nano-material family, has attracted more and more attention because of its unique nature and potential application value. Compared with the traditional organic dye and the semiconductor quantum dot, the carbon point not only inherits the advantages of wide raw material and low cost of the carbon nano-material, but also has the advantages of simple preparation, easy modification, tunable emission wavelength, good light stability, low toxicity and good biocompatibility, The electrocatalysis and the like also have special properties. Therefore, the carbon point has a wide application prospect in the fields of analysis detection, catalysis, photoelectric device, biological sensing and biological medical treatment. The carbon-point preparation method can be divided into top-down and bottom-up methods. The top-down method mainly includes the ultrasonic method, the laser ablation method, the electrochemical method and the like. The bottom-up method mainly includes the template method, the nitric acid reflux method, the microwave method, the hydrothermal method and the like. This paper, from the preparation of carbon point and its application, looks for green and environment-friendly materials as synthetic raw materials, and probes into the simple and rapid preparation method of carbon-point, and studies the application of it in the detection of folic acid and ciprofloxacin. The method mainly comprises the following two aspects: (1) using lactose as a carbon source, in a NaOH strong base solution environment, a carbon point with a light blue fluorescence is synthesized in one step by a hydrothermal method. It was characterized by high resolution transmission electron microscopy (HR-TEM) that the carbon point had a good dispersion and an average particle size of about 2-3 nm. The carbon-point surface was characterized by an infrared spectrum, and the carbon-point surface contained functional groups such as CH2, CH3, OH and COOH. Since the carbon point can be specifically combined with folic acid, we use a carbon spot as a fluorescent probe for the detection of folic acid. The mechanism may be that the water-soluble groups (OH and COOH) and the hydrophilic functional groups of the folic acid (OH, COOH, and NH2) interact with the hydrophilic functional groups (OH, COOH and NH2) of the folic acid to form hydrogen bonds, leading to the aggregation of the carbon points, leading to fluorescence quenching. The concentration of folic acid was in the range of 6-10-5 mol/ L-8 and 10-8 mol/ L, and the detection limit was 1.2-10-9 mol/ L. In addition, the system is used for the detection of folic acid in a human urine sample, and the recovery rate is between 96.7% and 103.0%, and the fluorescence analysis method established in this paper can be used for detecting the folic acid in the actual sample successfully. Folic acid, also known as vitamin B9, is a water-soluble vitamin, which plays an important role in the new metabolism of human body. Some diseases are closely related to the lack of folic acid, such as megaloblastic anemia, stroke, heart attack, psychosis, infant malformations, cancer, and the like. Therefore, it is of great significance to develop a convenient and fast analytical method for the detection of folic acid. (2) We used hydroxypropyl cellulose (HPMC) as a carbon source and prepared a carbon spot with blue fluorescence by a hydrothermal method. It is characterized by a fluorescence spectrum, a high-resolution transmission electron microscope, an ultraviolet-visible absorption spectrum, an infrared spectrum, an X-ray photoelectron spectrum, and the like. The carbon spot has a particle size of about 5.6 nm, a fluorescence quantum yield of 1.36%, a maximum excitation wavelength and a maximum emission wavelength of 310 nm and 420 nm, respectively, while finding that the carbon dot has a property of emission wavelength dependent on the excitation wavelength; and by structural characterization, It is found that the carbon-point surface is rich in water-soluble functional groups such as--OH and--COOH. And a new method for detecting ciprofloxacin is established by the combination of the carbon-point surface group and ciprofloxacin. The linear range is between 10 nM and 90. m u.M with a detection limit of 5.88 nM (3%), indicating that the detection range is wide and the sensitivity is high, indicating that the fluorescence analysis method established herein can be used for the detection of ciprofloxacin. Ciprofloxacin is a broad-spectrum antibacterial agent of the third generation, which has a good effect on the Gram-positive bacteria and the Gram-negative bacteria, and leads to the increase of the residue in the living body, so the detection of the trace residue is a significant work.
【学位授予单位】：西南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O657.3;R927
本文编号：2495968
[Abstract]:Carbon dot (CDs), as a new member of the carbon nano-material family, has attracted more and more attention because of its unique nature and potential application value. Compared with the traditional organic dye and the semiconductor quantum dot, the carbon point not only inherits the advantages of wide raw material and low cost of the carbon nano-material, but also has the advantages of simple preparation, easy modification, tunable emission wavelength, good light stability, low toxicity and good biocompatibility, The electrocatalysis and the like also have special properties. Therefore, the carbon point has a wide application prospect in the fields of analysis detection, catalysis, photoelectric device, biological sensing and biological medical treatment. The carbon-point preparation method can be divided into top-down and bottom-up methods. The top-down method mainly includes the ultrasonic method, the laser ablation method, the electrochemical method and the like. The bottom-up method mainly includes the template method, the nitric acid reflux method, the microwave method, the hydrothermal method and the like. This paper, from the preparation of carbon point and its application, looks for green and environment-friendly materials as synthetic raw materials, and probes into the simple and rapid preparation method of carbon-point, and studies the application of it in the detection of folic acid and ciprofloxacin. The method mainly comprises the following two aspects: (1) using lactose as a carbon source, in a NaOH strong base solution environment, a carbon point with a light blue fluorescence is synthesized in one step by a hydrothermal method. It was characterized by high resolution transmission electron microscopy (HR-TEM) that the carbon point had a good dispersion and an average particle size of about 2-3 nm. The carbon-point surface was characterized by an infrared spectrum, and the carbon-point surface contained functional groups such as CH2, CH3, OH and COOH. Since the carbon point can be specifically combined with folic acid, we use a carbon spot as a fluorescent probe for the detection of folic acid. The mechanism may be that the water-soluble groups (OH and COOH) and the hydrophilic functional groups of the folic acid (OH, COOH, and NH2) interact with the hydrophilic functional groups (OH, COOH and NH2) of the folic acid to form hydrogen bonds, leading to the aggregation of the carbon points, leading to fluorescence quenching. The concentration of folic acid was in the range of 6-10-5 mol/ L-8 and 10-8 mol/ L, and the detection limit was 1.2-10-9 mol/ L. In addition, the system is used for the detection of folic acid in a human urine sample, and the recovery rate is between 96.7% and 103.0%, and the fluorescence analysis method established in this paper can be used for detecting the folic acid in the actual sample successfully. Folic acid, also known as vitamin B9, is a water-soluble vitamin, which plays an important role in the new metabolism of human body. Some diseases are closely related to the lack of folic acid, such as megaloblastic anemia, stroke, heart attack, psychosis, infant malformations, cancer, and the like. Therefore, it is of great significance to develop a convenient and fast analytical method for the detection of folic acid. (2) We used hydroxypropyl cellulose (HPMC) as a carbon source and prepared a carbon spot with blue fluorescence by a hydrothermal method. It is characterized by a fluorescence spectrum, a high-resolution transmission electron microscope, an ultraviolet-visible absorption spectrum, an infrared spectrum, an X-ray photoelectron spectrum, and the like. The carbon spot has a particle size of about 5.6 nm, a fluorescence quantum yield of 1.36%, a maximum excitation wavelength and a maximum emission wavelength of 310 nm and 420 nm, respectively, while finding that the carbon dot has a property of emission wavelength dependent on the excitation wavelength; and by structural characterization, It is found that the carbon-point surface is rich in water-soluble functional groups such as--OH and--COOH. And a new method for detecting ciprofloxacin is established by the combination of the carbon-point surface group and ciprofloxacin. The linear range is between 10 nM and 90. m u.M with a detection limit of 5.88 nM (3%), indicating that the detection range is wide and the sensitivity is high, indicating that the fluorescence analysis method established herein can be used for the detection of ciprofloxacin. Ciprofloxacin is a broad-spectrum antibacterial agent of the third generation, which has a good effect on the Gram-positive bacteria and the Gram-negative bacteria, and leads to the increase of the residue in the living body, so the detection of the trace residue is a significant work.
【学位授予单位】：西南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O657.3;R927
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