铕基荧光探针的合成及其对水体中磷酸盐的检测

发布时间：2018-06-14 14:37

本文选题：磷酸盐 + 荧光分析法　；参考：《中国科学技术大学》2017年硕士论文

【摘要】：磷是自然界中一种极其重要的元素,但同时也是引起水体富营养化的主要元素之一。为了能够有效地控制富营养化,我们必须清楚水体中磷酸盐的含量。荧光分析法由于操作简单、灵敏度高和选择性好,近年来已成为环境检测领域备受关注的分析方法。稀土配位聚合物具有独特的荧光特性和结构可调整性,且镧系元素铕离子与磷酸盐具有较强的结合力,因此我们选择形貌可控的铂基配位聚合物(Eu-ICP)作为荧光探针来检测水体中的磷酸盐。另外,对于实际水样中的磷酸盐含量分析,定点定时的采样方法难以及时、全面、客观地反映水质安全状况以及磷酸盐的时空分布和化学状态,所以我们采用了薄膜梯度扩散(DGT)技术,并以碲化镉量子点(CdTe QDs)与铕离子组成的荧光探针作为其结合相,探索了它们在实际水体中原位检测磷酸盐的可行性与准确性。本文的研究成果如下:1、采用简单的溶剂热法一步合成形貌均匀的Eu-ICP纳米球,改变反应条件可调控其结构和形貌。该材料荧光性能优异,在水环境介质中结构稳定性好,其荧光强度在一定范围内基本不受溶液pH和离子强度等因素的影响,可作为一种有效的荧光探针来选择性地测定水体中的磷酸盐含量,线性检测范围是2～100μM,检测限为0.83μM。为了评估该荧光探针分析的准确性,Eu-ICP纳米球被用来检测实际水样中的磷酸盐含量,得到了令人满意的加标回收率和较低的相对标准差。此外,我们分析了 Eu-ICP纳米球检测磷酸盐的机理,并通过观察Eu-ICP纳米球与磷酸盐相互作用前后结构和形貌的变化进行了验证。总的来说,Eu-ICP纳米球易于合成,水溶性和稳定性良好,具有优异的选择性和灵敏度,可用于复杂水环境中的磷酸盐含量分析。2、通过油浴回流法合成了巯基乙酸包覆的CdTe QDs,其与镧系元素Eu~(3+)可组成荧光探针(CdTeQDs/Eu~(3+)),荧光强度在一定范围内受溶液pH和离子强度等因素的影响较小,并对磷酸盐具有优异的选择性响应,在10～200μM范围内呈现良好的线性关系,检测限为1.58μM。我们以该探针溶液作为DGT装置的结合相,将其放入已知浓度的磷酸盐溶液中,通过测定不同时间段的荧光强度计算得到了 CdTe QDs/Eu~(3+)-DGT的扩散系数,并以此来检测实际加标水样中的磷酸盐浓度,测试结果与标准钼蓝比色法的检测结果相近,证明了该分析方法的可行性与准确性。
[Abstract]:Phosphorus is an extremely important element in nature, but it is also one of the main elements that cause eutrophication of water body. In order to effectively control eutrophication, we must know the amount of phosphate in water. Due to its simple operation, high sensitivity and good selectivity, fluorescence analysis has been paid more and more attention in the field of environmental detection in recent years. Rare earth coordination polymers have unique fluorescence properties and adjustable structure, and the lanthanide europium ions have strong binding force with phosphate. Therefore, we selected Pt-based coordination polymer Eu-ICP as fluorescence probe to detect phosphate in water. In addition, for the analysis of phosphate content in real water samples, the fixed point timing sampling method is difficult to reflect the safety of water quality and the temporal and spatial distribution and chemical state of phosphate in a timely, comprehensive and objective manner. So we have used the thin film gradient diffusion technique and the fluorescence probe composed of cadmium telluride quantum dot CdTe QDsand europium ion as its binding phase to explore the feasibility and accuracy of in situ detection of phosphate in real water. The results are as follows: 1. The uniform Eu-ICP nanospheres are synthesized by a simple solvothermal method. The structure and morphology of Eu-ICP nanospheres can be controlled by changing the reaction conditions. The material has excellent fluorescence properties and good structural stability in water environment. The fluorescence intensity of the material is not affected by pH and ionic strength of the solution in a certain range. It can be used as an effective fluorescence probe for the selective determination of phosphate content in water. The linear detection range is 200 渭 m and the detection limit is 0.83 渭 M. In order to evaluate the accuracy of the fluorescence probe analysis, Eu-ICP nanospheres were used for the determination of phosphate in real water samples. The satisfactory recoveries and lower relative standard deviations were obtained. In addition, we analyzed the mechanism of phosphate detection by Eu-ICP nanospheres, and verified by observing the structure and morphology of Eu-ICP nanospheres before and after the interaction between Eu-ICP nanospheres and phosphate. Generally speaking, Eu-ICP nanospheres are easy to synthesize, have good water solubility and stability, excellent selectivity and sensitivity. The CdTe QDscoated with thioglycolic acid and lanthanide Euclide 3) were synthesized by oil bath reflux method, which can be used to form a fluorescence probe, CdTeQDs- EEU ~ (3 +). The fluorescence intensity of CdTe QDs / EU ~ (3 +) is determined by solution pH and dissociation in a certain range. The influence of factors such as sub-strength is relatively small, And it has excellent selective response to phosphate, and the linear relationship is good in the range of 10 渭 m to 200 渭 M. the detection limit is 1.58 渭 M. The probe solution was used as the binding phase of the DGT unit, and was put into the phosphate solution with known concentration. The diffusion coefficient of CdTe QDsr / Euf3 / DGT was calculated by measuring the fluorescence intensity at different time periods. The results are close to those of standard molybdenum blue colorimetry, which proves the feasibility and accuracy of the method.
【学位授予单位】：中国科学技术大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X832;O657.3

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