氮掺杂的荧光碳点的化学发光及其应用研究

发布时间：2018-07-22 15:16

【摘要】：化学发光法因其不需要光源,灵敏度高,线性范围宽和仪器简单等优点,已成为最有发展潜力的分析方法之一。近年来,随着纳米技术的不断发展,化学发光已从传统的分子体系扩展到纳米体系,从而极大地改善了化学发光的灵敏度并拓宽了其应用范围。氮掺杂的荧光碳点(NFCDs)作为一种由碳元素和氮元素组成的非金属纳米材料,具有良好的荧光性,优异的分散性和化学稳定性,以及较低的毒性等特点。目前,NFCDs主要作为荧光探针用于生物和环境检测方面,因此探究NFCDs参与的化学发光新体系具有极大的理论意义和应用价值。本研究工作中,以抗坏血酸和氨水为原料,通过简单的一步超声法合成NFCDs,并探究了其在新的化学发光体系中的作用。建立了三种基于NFCDs的流动注射化学发光的新方法,主要研究内容如下:1.在酸性介质中,KMn O4/Ce(IV)直接氧化NFCDs产生相对强的化学发光,硫脲/单宁的加入对KMnO_4-NFCDs体系的化学发光有明显的增敏作用,而对Ce(IV)-NFCDs体系的化学发光几乎没有影响,由此建立了用KMnO_4-NFCDs体系测定硫脲/单宁的新方法。在最佳实验条件下,测定硫脲和单宁的线性范围分别为1.0×10 7 1.0×10 5 mol/L和7.0×10 8 7.0×10 6 mol/L,检出限分别为3.8×10 8 mol/L和2.6×10 8 mol/L。将该方法分别用于橘汁和橘皮中硫脲含量的测定,以及五倍子中单宁含量的测定,获得满意的结果。2.Ce(IV)和Na_2SO_3反应产生微弱的化学发光,NFCDs对该体系的发光信号有显著的放大作用,加入吲哚乙酸后,Ce(IV)-Na_2SO_3-NFCDs体系的化学发光得到明显的抑制。由此建立了一种分析水样中痕量吲哚乙酸的新方法,标准曲线的浓度范围为2.0×10-8 1.0×10-6 mol/L,检出限为5.6×10-9 mol/L。3.在碱性条件下,NFCDs能明显增敏KMnO_4-luminol体系的化学发光,加入Mn~(2+)后,KMnO_4-luminol-NFCDs体系的化学发光强度得到明显的抑制。在最优的实验条件下,Mn~(2+)在3.0×10-7 5.0×10-5 mol/L浓度范围内与其化学发光的抑制值呈线性关系,检出限为4.3×10-8 mol/L。将该方法用于水样中Mn~(2+)含量的测定。
[Abstract]:Chemiluminescence has become one of the most promising analytical methods due to its advantages of no light source, high sensitivity, wide linear range and simple instrument. In recent years, with the development of nanotechnology, chemiluminescence has been extended from traditional molecular system to nano-system, which greatly improves the sensitivity of chemiluminescence and widens its application scope. Nitrogen-doped fluorescent carbon dots (NFCDs), as a nonmetallic nano-material composed of carbon and nitrogen elements, have good fluorescence, excellent dispersion and chemical stability, and low toxicity. Currently, NFCDs are mainly used as fluorescent probes for biological and environmental detection. Therefore, it is of great theoretical significance and practical value to explore the new chemiluminescence system in which NFCDs participate. In this study, ascorbic acid and ammonia were used as raw materials to synthesize NFCDs by a simple one-step ultrasonic method, and the role of NFCDs in the new chemiluminescence system was investigated. Three new flow injection chemiluminescence methods based on NFCDs were established. The main research contents are as follows: 1. In acidic medium, direct oxidation of NFCDs by KMnO4 / ce (IV) produces relatively strong chemiluminescence. The addition of thiourea / tannin can obviously increase the chemiluminescence of KMnO4-NFCDs system, but has little effect on the chemiluminescence of ce (IV) -NFCDs system. A new method for the determination of thiourea / tannin by KMnO4-NFCDs system was established. Under the optimum conditions, the linear ranges of thiourea and tannin were 1.0 脳 10 ~ (7) and 1.0 脳 10 ~ (5) mol / L, respectively, and the detection limits were 3.8 脳 10 ~ (8) mol / L and 2.6 脳 10 ~ (8) mol 路L ~ (-1), respectively. The method was applied to the determination of thiourea content in orange juice and orange peel, and tannin content in gallnut, respectively. The satisfactory results were obtained. 2. Ce (IV) and Na _ 2SO _ 3 reaction produced weak chemiluminescent NFCDs to amplify the luminescence signal of the system. The chemiluminescence of ce (IV) -Na _ 2SO _ 2SO _ 3-NFCDs system was obviously inhibited after indoleacetic acid was added. A new method for the determination of trace indoleacetic acid in water samples was established. The concentration range of the standard curve was 2.0 脳 10 ~ (-8) ~ (-1) 脳 10 ~ (-6) mol / L, and the detection limit was 5.6 脳 10 ~ (-9) mol / L ~ (-3). NFCDs can obviously sensitize the chemiluminescence of KMnO4-luminol system under alkaline condition, and the chemiluminescence intensity of KMnO4-luminol-NFCDs system can be inhibited obviously by adding Mn2 into KMnO4-luminol-NFCDs system. Under the optimum experimental conditions, there is a linear relationship between the chemiluminescence inhibition value and the concentration range of 3.0 脳 10 ~ (-7) 渭 mol / L ~ (-5) 脳 10 ~ (-5) mol 路L ~ (2). The detection limit is 4.3 脳 10 ~ (-8) mol 路L ~ (-1). The method has been applied to the determination of Mn2 in water samples.
【学位授予单位】：山西师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O657.3

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