荧光碳量子点的合成、性能及分析检测应用研究

发布时间：2018-06-18 00:51

本文选题：碳量子点 + 水热法　；参考：《宁夏大学》2017年硕士论文

【摘要】：碳量子点(简称碳点)作为一种新型的零维碳纳米材料,具有粒径小、毒性低、生物相容性好、激发光连续,发射光可调等优点。与传统荧光材料相比,碳量子点具有更为突出的光学特性及优越的性能,所以其在生物成像、光电器件、催化、生物传感等领域都表现出十分重要的应用价值。本论文采用不同的碳源,通过水热法辅助硝酸氧化法制备出了性能优良碳量子点,并且对合成的荧光碳点进行元素掺杂以提高碳量子点的荧光性能。利用合成的荧光碳量子点构建了检测的过氧化氢、Fe2+、Fe3+、L-半胱氨酸、Hg2+以及有机磷农药的光学传感方法。具体研究内容如下:1、以玉米秸秆为碳源,采用一步水热法合成了发蓝绿色荧光的碳量子点(CDs),并对合成的碳量子点进行了 TEM、XRD、XPS、FTIR等表征,证实了合成的CDs表面被羧基、羟基、氨基、羰基等官能团所功能化;荧光碳量子点粒径在5.2nm左右并且具有良好的分散性和水溶性,量子点产率达到了 7.6%。研究发现过氧化氢和Fe2+同时存在的条件下,CDs的荧光会发生猝灭,基于此原理实现了对过氧化氢和Fe2+灵敏的检测,最低检测线为0.18 μmnol/L和0.21 μmol/L。2、采用太西煤为碳源,通过硝酸氧化法及水热辅助合成了发黄色荧光的石墨烯量子点(GQDs),实验中对比了硝酸氧化法制备的GQDs与水热辅助合成的GQDs的荧光性能,通过对两种方法合成的GQDs进行了 TEM、XPS、FTIR、UV-vis等表征,对比分析了 GQDs的结构性能,合成的GQDs的粒径在4.5 nm左右。基于Fe3+可以使GQDs的荧光发生猝灭的原理,实现了灵敏的检测Fe3+,在PBS缓冲溶液中(0.02mol/LpH=3.02),GQDs的荧光强度与Fe3+的浓度在0-21 μmol/L范围内呈良好的线性关系,最低检测线为0.67nmol/L,并将本方法应用到对水样中Fe3+的检测。3、以海藻酸为碳源,氢氧化镁和三乙醇胺为修饰试剂,通过一步水热法合成了水溶性好且稳定性高的镁氮共掺杂的碳量子点(Mg,N-CDs)。研究发现Hg2+对碳量子点荧光强度有良好的猝灭作用,当加入L-半胱氨酸时,碳量子点的荧光强度又会恢复,基于荧光开关的原理,可以快速、灵敏且选择性好的检测Hg2+和L-半胱氨酸。实验结果表明:在pH=7的磷酸盐缓冲溶液中碳量子点的荧光强度与Hg2+浓度在0-45 μmol/L范围内呈良好的线性关系,最低检测限为0.17 μmol/L。L-半胱氨酸的检测范围在0-55 mol/L,最低检测限为0.09 μmol/L。4、镁氮共掺杂的碳量子点可以作为一种荧光探针高灵敏度和选择性的检测有机磷农药的中的对氧磷。当体系中分别加入解磷定(PAM)和有机磷农药(OPs)时,Mg,N-CDs的荧光强度基本上没有发生变化,当同时加入PAM和OPs时,碳量子点的荧光强度会明显的猝灭。本章还考察了检测条件如:pH、反应时间,PAM的浓度对检测有机磷的影响。在最佳检测条件下,有机磷的检测范围为0.05-45 μmol/L,最低检测限为0.87 μmol/L。
[Abstract]:Carbon quantum dots (carbon dots), as a new kind of zero-dimensional carbon nanomaterials, have the advantages of small particle size, low toxicity, good biocompatibility, continuous excitation light and adjustable emission light. Compared with traditional fluorescent materials, carbon quantum dots (QDs) have more outstanding optical properties and superior properties, so they have important application value in biological imaging, optoelectronic devices, catalysis, biosensor and so on. In this paper, carbon quantum dots with excellent properties were prepared by hydrothermal assisted nitric acid oxidation with different carbon sources, and the synthesized carbon dots were doped with elements to improve the fluorescence properties of carbon quantum dots. An optical sensing method for the determination of Fe _ 2H _ 2O _ 2, Fe _ 3, L-cysteine, Hg2 and organophosphorus pesticides was constructed by using the synthesized fluorescent carbon quantum dots (FQDs). The specific research contents are as follows: 1. Using corn straw as carbon source, a blue-green fluorescent carbon quantum dot (CDsN) was synthesized by a one-step hydrothermal method. The synthesized QDs were characterized by TEMN XRDX PSN FTIR and the surface of the synthesized CDs was confirmed by carboxyl group, hydroxyl group, amino group, etc. The particle size of fluorescent carbon quantum dots is about 5.2nm and has good dispersion and water solubility. The yield of quantum dots reaches 7.6. It was found that the fluorescence of CDs would be quenched under the condition of both hydrogen peroxide and Fe _ 2. Based on this principle, the sensitive detection of hydrogen peroxide and Fe _ 2 was realized. The lowest detection line was 0.18 渭 mol / L and 0.21 渭 mol / L ~ (-2), and the coal was used as carbon source. GQDs with yellow fluorescence were synthesized by nitric acid oxidation and hydrothermal assisted synthesis. The fluorescence properties of GQDs prepared by nitric acid oxidation and hydrothermal assisted synthesis were compared. The GQDs synthesized by the two methods were characterized by the UV-vis method. The structure and properties of the synthesized GQDs were compared and analyzed. The size of the synthesized GQDs was about 4.5 nm. Based on the principle that Fe _ 3 can quench the fluorescence of GQDs, a sensitive method for the detection of Fe _ 3 has been achieved. The fluorescence intensity of GQDs in PBS buffer solution is in good linear relationship with the concentration of Fe _ 3 in the range of 0-21 渭 mol 路L ~ (-1), and the fluorescence intensity of GQDs is 0.02mol / L ~ 3.02mol / L in PBS buffer solution. The lowest detection line was 0.67 nmol / L, and the method was applied to the determination of Fe _ 3 in water samples by using alginic acid as carbon source, magnesium hydroxide and triethanolamine as modifiers. Mg-N doped carbon quantum dots (MQDs) with good water solubility and high stability were synthesized by one step hydrothermal method. It is found that Hg _ 2 has a good quenching effect on the fluorescence intensity of carbon quantum dots. When L- cysteine is added, the fluorescence intensity of carbon quantum dots will recover again. Based on the principle of fluorescence switch, the fluorescence intensity of carbon quantum dots can be recovered quickly. Sensitive and selective detection of Hg 2 and L-cysteine. The experimental results show that the fluorescence intensity of carbon quantum dots in phosphate buffer solution at pH 7 has a good linear relationship with the concentration of Hg _ 2 in the range of 0-45 渭 mol / L. The lowest detection limit is 0.17 渭 mol / L L- cysteine in the range of 0-55 mol / L, and the lowest detection limit is 0.09 渭 mol / L. 4. The magnesia-nitrogen co-doped carbon quantum dots can be used as a fluorescent probe to detect p-oxyphosphorus in organophosphorus pesticides with high sensitivity and selectivity. The fluorescence intensity of MgN-CDs was basically unchanged when PAM) and OPs were added respectively. When PAM and ops were added at the same time, the fluorescence intensity of carbon quantum dots was obviously quenched. The influence of the concentration of PAM on the determination of organophosphorus was also investigated. Under the optimum conditions, the detection range of organophosphorus was 0.05-45 渭 mol / L, and the minimum detection limit was 0.87 渭 mol / L.
【学位授予单位】：宁夏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O657.3;TB383.1

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