基于聚集荧光增强机理的铀酰离子荧光探针的设计合成及在核燃料循环中的分析应用

It is critical to detect trace uranium, the principal element in nuclear fuel, with high sensitivity and selectivity. Organic sensors theoretically have better selectivity and higher stability. However, a difficulty in designing organic sensors for uranium is that the fluorescence intensity of sensors will always be quenched by solubilized uranyl ions. .We propose to use organic molecules with aggregation-induced emission enhancement (AIEE) properties, taking advantage of their high fluorescence efficiency at aggregated/solid state to mitigate the problem of fluorescence quenching. By introducing moieties in sensor molecules that can specifically ligand or catalytically react with uranyl ions between the dispersed state in solution and aggregated state, the AIEE fluoresncece signal can consequently be improved. With this approach we will construct detection systems with fluorescence-on or ratio fluorescence signals for trace uranium detection. .We will use such sensor systems in the detection of trace uranium in nuclear fuel cycles. In addition, sensors with advantageous detection features will be modified on solid silica thin films with nano/micro-pores, allowing for concentration enrichment of uranium prior to analysis and further improve detection reproducibility.This project will represent new mechanisms and applications of fluorescent methods for detecting trace uranium, and the results obtained will also make a positive promotion of uranium detection techniques in nuclear fuel cycle processes.

铀是目前最重要的核燃料来源，痕量铀的分析检测对环境保护、辐射防护以及提高铀燃料经济性等方面都有十分重要的意义。荧光分析法是痕量铀分析检测的重要方法之一。为了克服传统有机荧光探针信号容易被铀酰离子淬灭的问题，本课题拟以席夫碱类聚集荧光增强型有机分子为母体，通过引入能够与铀酰离子发生特异性相互作用的基团，使荧光探针发生分散态与聚集态之间的转变，由此构建对铀酰离子具有荧光增强或双波长比率型响应的荧光探针体系。进而，结合多孔材料的优势，将筛选得到的性能优异的荧光探针修饰在介孔/微孔二氧化硅薄膜上，开发固态荧光探针体系，进一步提高检测方法的灵敏度和可重复性。在此基础上，根据实际样品检测要求进一步优化探针性能，建立具有高选择性、高灵敏度的铀酰离子荧光分析方法，最终实现对实际样品中的铀含量的分析，为核燃料循环领域中痕量铀的检测提供新的快速、高效的荧光检测技术。

铀是目前最重要的核燃料来源，高灵敏度、高选择性的铀含量分析检测在核燃料循环中占有举足轻重的地位。荧光分析法是痕量铀分析检测的重要方法之一。但是，目前针对溶液中痕量铀检测的无机类荧光探针存在抗干扰能力差、低温条件下易结晶等问题，而有机类探针的荧光信号在溶液中则很容易被淬灭。席夫碱类聚集荧光增强型有机荧光探针，其荧光模式在理论上能够克服传统有机类探针的荧光淬灭问题，具有较强铀酰离子络合能力的席夫碱结构还有助于提高探针的选择性。本课题以上述类型的分子结构为母体，通过引入能够与铀酰离子发生特异性相互作用的基团，使分子与铀酰离子发生分散态与聚集态之间的转变，构建了对铀酰离子具有荧光增强或及双波长比率型响应的荧光探针体系。本课题还将筛选得到的性能优异的荧光探针修饰在二氧化硅及碳量子点固态材料上，构建了固态荧光探针体系，提高检测方法的灵敏度和可重复性，最终应用于实际核燃料循环样品中痕量铀的分析检测。