氮掺杂石墨烯量子点荧光检测体系的构建及分析应用研究
发布时间：2018-10-26 16:47
【摘要】：石墨烯量子点(GQDs)是一种新型的具有荧光性能的碳基准零维纳米材料,其定义为横向尺寸小于100 nm的单层、双层和3-10层的石墨烯片。GQDs的比表面积大且外边缘有羟基和羧基等基团,因此具有易于修饰的特点。在经过化学修饰的量子点中,化学键合氮原子合成的氮掺杂石墨烯量子点(N-GQDs)与GQDs相比具有量子产率高、荧光强度高、水溶性好、生物毒性低、生物相容性好等优势,因此在荧光检测、环境监测、光电器件、生物成像等领域中具有良好的发展前景。在本论文工作中,结合本实验室在量子点制备方面的基础工作,分别以柠檬酸和脲作为碳源和氮源,采用水热法一步合成了N-GQDs,并分别用紫外-可见光谱、透射电子显微镜、X射线衍射仪、X射线光电子能谱及荧光光谱对其进行了表征,研究其结构特性,构建了N-GQDs相关的荧光检测体系,并进一步对实际样品中四环素(TC)、抗坏血酸(AA)、铁的形态进行了分析。主要内容如下:1.N-GQDs在TC定量检测中的应用。通过水热法一步合成了平均直径为4.4±0.6nm的N-GQDs,与GQDs相比具有更强的荧光性质,在pH和离子强度等条件下更稳定,并表现出蓝移的特性。在优化pH、反应温度、反应时间等实验条件的基础上,利用TC对N-GQDs的荧光猝灭作用建立了一种测定TC的荧光分析新方法,检测TC的线性范围为0.20 20μmol·L-1,检出限(3σ,n=11)为1.62 nmol·L-1。与其他的分析技术相比,此荧光猝灭方法从检测限、线性范围等方面都展现出更优良的分析性能,并成功应用于检测牛奶样品中TC的含量。2.N-GQDs在AA定量检测中的应用。基于Fe(Ⅲ)和Fe(II)对N-GQDs荧光的不同猝灭效果,发展了一种荧光增强型探针并应用于饮料样品中AA的选择性检测。首先通过N-GQDs和Fe(Ⅲ)之间的非辐射电子转移猝灭N-GQDs的荧光以测定Fe(Ⅲ),加入AA后,Fe(Ⅲ)与AA之间发生氧化还原反应使Fe(Ⅲ)转化为Fe(II),因为Fe(II)对N-GQDs的荧光无明显猝灭作用,从而导致N-GQDs荧光得以恢复。该传感器对AA有很好的选择性,线性范围为1.0 90μmol·L-1,检出限(3σ,n=11)是18 nmol·L-1,并成功应用于测定饮料样品中AA的含量。3.N-GQDs在铁形态分析中的应用。基于Fe(Ⅲ)对N-GQDs的荧光猝灭效果测定Fe(Ⅲ),并分别对自然水样中的Fe(II)和Fe(Ⅲ)进行定量分析,达到对铁进行形态分析的目的。首先通过Fe(Ⅲ)对N-GQDs的荧光猝灭作用测定Fe(Ⅲ)和总铁浓度,Fe(tot)中包括过氧化氢氧化Fe(II)得到的Fe(Ⅲ),Fe(II)可以从Fe(tot)中减去Fe(Ⅲ)得到。检测Fe(Ⅲ)的线性范围为0.0100-200μmol·L-1,检出限(3σ,n=11)为4.24 nmol·L-1,这种方法与之前报道过的铁形态分析方法相比简单且避免了冗杂的实验配置,具有灵敏度高、易于操作等优点,并且实验结果表明该方法可以对自然水体中的溶解铁进行形态分析。
[Abstract]:Graphene Quantum Dot (GQDs) is a new carbon reference zero dimensional nano-material with fluorescence properties, which is defined as a single layer with transverse size less than 100 nm. The surface area of GQDs is large and there are hydroxyl and carboxyl groups on the outer edge, so it is easy to modify. In chemically modified quantum dots, nitrogen-doped graphene quantum dots (N-GQDs) synthesized by chemically bonded nitrogen atoms have the advantages of higher quantum yield, higher fluorescence intensity, better water solubility, lower biotoxicity and better biocompatibility than those of GQDs. Therefore, it has a good prospect in the fields of fluorescence detection, environmental monitoring, optoelectronic devices, biological imaging and so on. In this paper, N-GQDs were synthesized by hydrothermal method with citric acid and urea as carbon source and nitrogen source, respectively, combined with the basic work of our laboratory in the preparation of quantum dots. Transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and fluorescence spectroscopy (FRS) were used to characterize the structure of the system. The N-GQDs related fluorescence detection system was constructed, and the tetracycline (TC), in real samples was further determined. The morphology of (AA), iron ascorbic acid was analyzed. The main contents are as follows: the application of 1.N-GQDs in quantitative detection of TC. N-GQDs with an average diameter of 4.4 卤0.6nm were synthesized by hydrothermal method in one step. Compared with GQDs, N-GQDs have stronger fluorescence properties and are more stable under the conditions of pH and ionic strength, and exhibit the characteristics of blue shift. On the basis of optimizing the reaction temperature and reaction time of pH, a new method for the determination of TC by fluorescence quenching of N-GQDs by TC was established. The linear range of detection of TC was 0.20 渭 mol L ~ (-1). The detection limit (3 蟽, nni11) is 1. 62 nmol L ~ (-1). Compared with other analytical techniques, this fluorescence quenching method showed better analytical performance in terms of detection limit and linear range, and was successfully applied to the determination of TC in milk samples. 2.N-GQDs was applied to the quantitative detection of AA. Based on the different quenching effects of Fe (鈪，
本文编号：2296368
[Abstract]:Graphene Quantum Dot (GQDs) is a new carbon reference zero dimensional nano-material with fluorescence properties, which is defined as a single layer with transverse size less than 100 nm. The surface area of GQDs is large and there are hydroxyl and carboxyl groups on the outer edge, so it is easy to modify. In chemically modified quantum dots, nitrogen-doped graphene quantum dots (N-GQDs) synthesized by chemically bonded nitrogen atoms have the advantages of higher quantum yield, higher fluorescence intensity, better water solubility, lower biotoxicity and better biocompatibility than those of GQDs. Therefore, it has a good prospect in the fields of fluorescence detection, environmental monitoring, optoelectronic devices, biological imaging and so on. In this paper, N-GQDs were synthesized by hydrothermal method with citric acid and urea as carbon source and nitrogen source, respectively, combined with the basic work of our laboratory in the preparation of quantum dots. Transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and fluorescence spectroscopy (FRS) were used to characterize the structure of the system. The N-GQDs related fluorescence detection system was constructed, and the tetracycline (TC), in real samples was further determined. The morphology of (AA), iron ascorbic acid was analyzed. The main contents are as follows: the application of 1.N-GQDs in quantitative detection of TC. N-GQDs with an average diameter of 4.4 卤0.6nm were synthesized by hydrothermal method in one step. Compared with GQDs, N-GQDs have stronger fluorescence properties and are more stable under the conditions of pH and ionic strength, and exhibit the characteristics of blue shift. On the basis of optimizing the reaction temperature and reaction time of pH, a new method for the determination of TC by fluorescence quenching of N-GQDs by TC was established. The linear range of detection of TC was 0.20 渭 mol L ~ (-1). The detection limit (3 蟽, nni11) is 1. 62 nmol L ~ (-1). Compared with other analytical techniques, this fluorescence quenching method showed better analytical performance in terms of detection limit and linear range, and was successfully applied to the determination of TC in milk samples. 2.N-GQDs was applied to the quantitative detection of AA. Based on the different quenching effects of Fe (鈪，
本文编号：2296368
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