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熒光碳點(diǎn)的制備及其在葉酸和環(huán)丙沙星檢測(cè)中的應(yīng)用

發(fā)布時(shí)間:2019-06-09 23:05
【摘要】:碳點(diǎn)(Carbon dots,CDs)作為碳納米材料家族的一名新成員,由于其具有獨(dú)特的性質(zhì)及潛在的應(yīng)用價(jià)值,受到越來(lái)越多人的關(guān)注。相比于傳統(tǒng)的有機(jī)染料和半導(dǎo)體量子點(diǎn),碳點(diǎn)不但繼承了碳納米材料原料廣泛、成本低的優(yōu)點(diǎn),還具有制備簡(jiǎn)單、易于修飾、發(fā)射波長(zhǎng)可調(diào)諧、光穩(wěn)定性好、毒性低和生物相容性好等優(yōu)勢(shì),同時(shí)在光、電催化等方面也具有特殊的性質(zhì)。因此,碳點(diǎn)在分析檢測(cè)、催化、光電器件、生物傳感以及生物醫(yī)療等領(lǐng)域呈現(xiàn)出廣闊的應(yīng)用前景。碳點(diǎn)的制備方法可以分為:自上而下法和自下而上法。自上而下法主要包括:超聲法,激光消融法,電化學(xué)法等。自下而上法主要有:模板法,硝酸回流法,微波法,水熱法等。本文從碳點(diǎn)的制備及其應(yīng)用兩個(gè)方面出發(fā),尋找綠色環(huán)保的物質(zhì)作為合成原料,探索碳點(diǎn)簡(jiǎn)便快捷的制備方法,并研究其在葉酸和環(huán)丙沙星檢測(cè)中的應(yīng)用。具體主要包括以下兩個(gè)方面:(1)以乳糖為碳源,在NaOH強(qiáng)堿溶液環(huán)境中,通過(guò)水熱法一步合成具有淡藍(lán)色熒光的碳點(diǎn)。隨后,對(duì)其進(jìn)行以下表征:通過(guò)高分辨透射電子顯微鏡(HR-TEM)觀察,碳點(diǎn)的分散性好,平均粒徑約為2-3 nm;通過(guò)紅外光譜表征,碳點(diǎn)表面含有 CH2、 CH3、 OH和 COOH等官能團(tuán)。由于碳點(diǎn)能與葉酸特異性結(jié)合,因此我們以碳點(diǎn)作為熒光探針用于檢測(cè)葉酸。其機(jī)理可能為:碳點(diǎn)表面的水溶性基團(tuán)( OH和 COOH)和葉酸的親水官能團(tuán)( OH、 COOH和 NH2)相互作用,形成氫鍵,促使碳點(diǎn)發(fā)生聚集,從而導(dǎo)致熒光猝滅。通過(guò)條件優(yōu)化,葉酸的濃度在6×10-5 mol/L-8×10-8 mol/L與碳點(diǎn)的熒光強(qiáng)度猝滅值呈線性相關(guān),檢測(cè)限為1.2×10-9mol/L。此外,該體系用于人體尿液樣品中葉酸的檢測(cè),回收率在96.7%-103.0%之間,說(shuō)明本文建立的熒光分析方法能成功用于實(shí)際樣品中葉酸的檢測(cè)。葉酸,又稱維生素B9,是一種水溶性維生素,在人體的新生代謝扮演著重要的作用。一些疾病與葉酸的缺乏密切相關(guān),例如:巨幼紅細(xì)胞性貧血,中風(fēng),心臟病發(fā)作,精神病,嬰兒畸形,癌癥等。因此,開(kāi)發(fā)方便快捷的分析方法用于檢測(cè)葉酸,具有重要意義。(2)我們以羥丙纖維素(HPMC)作為碳源,通過(guò)水熱法制備了發(fā)藍(lán)色熒光的碳點(diǎn)。通過(guò)熒光光譜、高分辨透射電鏡、紫外-可見(jiàn)吸收光譜、紅外光譜、X射線光電子能譜等手段對(duì)其進(jìn)行表征。碳點(diǎn)的粒徑大小約為5.6 nm,熒光量子產(chǎn)率為1.36%;最大激發(fā)波長(zhǎng)和最大發(fā)射波長(zhǎng)分別為310 nm和420 nm,同時(shí)發(fā)現(xiàn)碳點(diǎn)具有發(fā)射波長(zhǎng)依賴于激發(fā)波長(zhǎng)的性質(zhì);通過(guò)結(jié)構(gòu)表征,發(fā)現(xiàn)碳點(diǎn)表面富含-OH和-COOH等水溶性官能團(tuán)。利用碳點(diǎn)表面基團(tuán)能與環(huán)丙沙星結(jié)合,建立了檢測(cè)環(huán)丙沙星的新方法。其線性范圍在10 nM-90μM之間,檢測(cè)限為5.88 nM(3σ),說(shuō)明其檢測(cè)范圍較寬和靈敏度高,表明本文建立的熒光分析方法可以用于環(huán)丙沙星的檢測(cè)。環(huán)丙沙星是第三代喹諾酮類廣譜抗菌藥,由于其對(duì)革蘭性陽(yáng)性菌和革蘭性陰性菌都有良好的效果,導(dǎo)致其在生物體殘留增多,所以對(duì)其痕量殘留進(jìn)行檢測(cè)是一項(xiàng)很有意義的工作。
[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.
【學(xué)位授予單位】:西南大學(xué)
【學(xué)位級(jí)別】:碩士
【學(xué)位授予年份】:2017
【分類號(hào)】:O657.3;R927

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