【作者】 孙鹏；

【导师】 柴芳；

【作者基本信息】 哈尔滨师范大学 ， 无机化学， 2024， 硕士

【摘要】 碳点（CDs）因其优异的光学性质、可谐调荧光、低毒性和易表面修饰等优势,而成为最具应用潜力的化学传感荧光纳米材料。生物质作为一种生态友好的碳自然资源,在合成CDs方面比其他碳质前体更具低成本、易获取和低毒性的优势。因此,本工作对基于生物质碳点的可控合成及其荧光检测性能进行了系统的探究。考虑到单信号分析在复杂环境中的应用可能会受到限制,设计并发展了基于CDs的多模式分析探针,对环境中多种分析物同时进行识别和检测,并利用多种信号进行分析,实现多元检测。此外,鉴于智能手机辅助分析能够实现更低成本且操作简单便捷,开发了基于CDs的手机集成传感策略。本工作不仅对CDs合成优化的方法进行了更为详细的探究,为目标CDs光学特性的谐调提供了一种思路,还为环境分析和食品安全开发了有前景的多功能探针。首先,利用蒲公英的乙醇浸取液作为前体,通过高温谐调以溶剂热法分别制备了红光发射碳点（R-CDs）和蓝光发射碳点（B-CDs）。基于其良好的光学特性和对水的特异性选择,可作为荧光探针,分别对乙醇、乙腈和丙酮溶剂中的水分子百分含量进行荧光检测。通过对白酒中的水百分含量进行分析,能够证实R-CDs作为荧光探针的可行性。B-CDs具有突出的荧光稳定性和环境耐受性。一定浓度的2,4-二硝基苯酚（DNP）会引起B-CDs发生较为显著的荧光淬灭现象,同时溶液颜色变黄。以此,可建立基于B-CDs的多模式荧光/比色检测平台对DNP进行分析,且不同检测方法可以相互验证,提高检测的准确性。此外,为了使检测过程更加方便迅速,将智能手机与R-CDs/B-CDs结合,同时拓展试纸和电纺纳米纤维膜（B-CDs-ENM）传感器,建立智能手机辅助的R-CDs/B-CDs传感平台,能够实现快速准确的实时现场测定,表现出潜在的应用前景。另外,通过调节合适的前驱体比例和反应条件,设计和合成具有优异稳定性和发光效率的蓝色荧光的铁和氮共掺杂碳点（AFC-CDs）,并开发了一种出色的双模式荧光/比色分析方法。基于静态淬灭和荧光共振能量转移机制,DA显著淬灭了AFC-CDs的荧光,并由于静电吸引产生了深棕色复合物。得益于特定的络合反应和双通道信号输出,AFC-CDs双模荧光/比色探针对DA具有良好的选择性和灵敏度。值得注意的是,AFC-CDs在真实样品中的DA分析中仍然保持了强大的可靠性和实用性。本研究为在复杂基质中对痕量DA的检测提供了一个可信赖的平台,并可扩展到在环境和食品安全领域的广泛应用。选取黄柏粉（PCS）、二乙烯三胺（DETA）和柠檬酸铁胺（AFC）作为原材料,一锅水热法制备了亮蓝色荧光发射的碳点（PCS-CDs）。Hg²⁺的加入会显著淬灭PCS-CDs蓝色荧光,由此可作为检测Hg²⁺的荧光探针并进行优化。将智能手机与PCS-CDs相结合,可建立手机辅助的PCS-CDs荧光传感平台,能够实现对Hg²⁺更便携即时的检测。值得注意的是,PCS-CDs还可以作为类过氧化物酶参与PCS-CDs-H₂O₂-TMB比色体系的构建,可实现对H₂O₂、DA和GSH的连续测定。作为一种双通道的荧光/比色探针,PCS-CDs在真实水样和小鼠血清样品的检测中展示了可靠的分析结果,显示出PCS-CDs在传感分析领域巨大的应用潜力。更多还原

【Abstract】 Carbon dots（CDs）were regarded as the most promising fluorescent nanomaterials for chemical sensing due to their excellent optical properties,tunable fluorescence,low toxicity and easy surface modification.Biomass,as an eco-friendly carbon natural resource,has the advantages of low cost,easy access and low toxicity compared with other carbonaceous precursors in the synthesis of CDs.Therefore,the controllable synthesis of CDs based on biomass and its fluorescence detection performance were systematically explored in this work.Considering the application of single signal analysis in complex environment may be limited,a multi-mode analysis probe based on CDs was designed and developed to identify and detect multiple analytes in the environment at the same time,and multiple signals were used to analyze and realize multivariate detection.In addition,in view of the fact that smart phone aided analysis could achieve lower cost and simple and convenient operation,a mobile phone integrated sensing strategy based on CDs was developed.This work not only explored the optimization method of CDs synthesis in more detail and provided an idea for the harmonization of optical properties of target CDs,but also developed a promising multifunctional probe for environmental analysis and food safety.Firstly,red-emitting CDs（R-CDs）and blue-emitting CDs（B-CDs）were prepared by solvothermal method with ethanol extract of Taraxacum mongolicum as precursor.Based on its good optical properties and specific selection of water,it could be used as a fluorescent probe to detect the percentage of water in ethanol,acetonitrile and acetone respectively.By analyzing the percentage of water in chinese hard liquor,the feasibility of R-CDs as a fluorescent probe was verified.B-CDs has outstanding fluorescence stability and environmental tolerance.2,4-dinitrophenol（DNP）with a certain concentration could cause obvious fluorescence quenching of B-CDs,and the color of the solution turned yellow.In this way,a multi-mode fluorescence/colorimetric detection platform based on B-CDs could be established to analyze DNP,and different detection methods could be mutually verified to improve the detection accuracy.In addition,in order to make the detection process more convenient and rapid,the mobile phone integrated with R-CDs/B-CDs,and at the same time expanded the test paper and the electrospun nanofiber membrane（B-CDs-ENM）sensor,and established mobile phone-assisted R-CDs/B-CDs sensing platform,which can realize rapid and accurate real-time on-site measurement and show potential application prospects.In addition,by adjusting the appropriate precursor ratio and reaction conditions,the blue fluorescent Fe and N co-doped CDs（AFC-CDs）with excellent stability and luminous efficiency were designed and synthesized,and an excellent dual-mode fluorescence/colorimetric analysis method was developed.Based on the mechanism of static quenching and fluorescence resonance energy transfer,DA significantly quenched the fluorescence of AFC-CDs,and a dark brown complex was produced due to electrostatic attraction.Benefit from specific complexation reaction and dual-channel signal output,AFC-CDs dual-mode fluorescence/colorimetric probe exhibited good selectivity and sensitivity to DA.Notably,AFC-CDs still maintained strong reliability and practicability in DA analysis in real samples.This study provided a reliable platform for the detection of trace DA in complex matrix,and can be extended to a wide range of applications in the fields of environment and food safety.Using cypress powder（PCS）,diethylenetriamine（DETA）and ferric ammonium citrate（AFC）as raw materials,bright blue fluorescent carbon dots（PCS-CDs）were prepared by one-pot hydrothermal method.The introduction of Hg²⁺could quench the fluorescence signal of PCS-CDs probe significantly,so it could be used as a fluorescent probe for detecting Hg²⁺and optimized.By combining smart phone with PCS-CDs,a mobile phone-assisted PCS-CDs fluorescence sensing platform was established,which achieved more portable and real-time detection of Hg²⁺.Notably,PCS-CDs could also be used as a peroxidase to participate in the construction of the colorimetric system of PCS-CDs-H₂O₂-TMB,which could realize the continuous determination of H₂O₂,DA and GSH.As a dual-channel fluorescence/colorimetric probe,PCS-CDs has demonstrated reliable analytical results in the detection of real water samples and mouse serum samples,showing its great application potential in the field of sensor analysis.更多还原