【作者】 周艳；

【导师】 郑佳红；

【作者基本信息】 长安大学 ， 材料与化工（专业学位）， 2023， 硕士

【摘要】 近年来,基于荧光碳量子点（CQDs）的荧光分析法因具有高灵敏度、快速、简单的优点,被广泛用于生物医药、环境监测等领域。本论文主要基于CQDs制备了四种荧光传感器,用于环丙沙星（CIP）、NO₃^–、PO₄^3–、抗坏血酸（AA）及Ce⁴⁺的荧光检测,具体内容包括以下方面:1.以葡萄糖为碳源,采用水热法制备CQDs,结合了稀土元素配合物以及比率荧光传感器的双重优点,构建了具有高灵敏度的CQDs/Eu³⁺的比率荧光传感器,用于CIP的检测。在395 nm波长激发下,CQDs/Eu³⁺在459 nm处存在较强的蓝色荧光峰,在616nm处存在较弱的红色荧光峰,当CIP存在时,基于电荷转移和氢键相互作用使得459nm处的CQDs荧光强度增强。研究优化了CQDs和Eu³⁺比例、响应时间、稳定性等实验条件,结果表明:该比率荧光传感器对CIP具有特异性识别能力,荧光强度比(F₄₅₉/F₆₁₆)与不同浓度CIP（0～7μM）之间存在良好的线性关系,对CIP的最低检测限为0.3μM,成功用于CIP的精确灵敏检测。2.采用水热法,将发射蓝色荧光的Ui O-66-NH₂与发射黄色荧光的CQDs（Y-CQDs）结合,构建了Ui O-66-NH₂@Y-CQDs比率荧光传感器,用于高选择性地检测NO₃^–。通过XRD、FT IR、SEM及TEM对其结构和形貌、荧光光谱对其光学性能进行表征,当NO₃^–浓度变化时,由于配体–金属电荷转移（LMCT）效应减弱,Ui O–66–NH₂的荧光增强;此外,NO₃^–和Y-CQDs作用促进了电荷转移导致Y-CQDs的荧光猝灭,使413 nm处的蓝色荧光与564 nm处的黄色荧光强度分别随着NO₃^–浓度的增加发生增强和减弱,结果表明:在最优条件下,F₄₁₃/F₅₆₄与NO₃^–在1～10μM浓度范围内呈现良好的线性关系,最低检测限为0.85μM,且对一些可能共存的物质做了相关的干扰探究,成功用于NO₃^–高灵敏度检测和选择性识别。3.采用水热法合成了高荧光性的CQDs,将CQDs封装在沸石咪唑骨架-8（ZIF-8）中,根据ZIF-8的二级散射光（SOS）和CQDs的荧光,构建了CQDs@ZIF-8比率荧光传感器,用于PO₄^3–的检测。通过XRD、FT IR、SEM及TEM对复合材料进行结构及形貌分析,用荧光光谱分析荧光性能,添加PO₄^3–后,PO₄^3–会与ZIF-8中的Zn²⁺选择性地反应,使ZIF-8裂解释放出CQDs,引起CQDs的荧光恢复和SOS强度降低。结果表明:在最优条件下,F₄₃₇/S₇₃₂与PO₄^3–在1～40μM浓度范围内呈现良好的线性关系,最低检测限为0.23μM,且对一些可能共存的物质做了相关的干扰探究,成功用于PO₄^3–的快速检测和选择性识别。4.采用水热法合成氮,硫掺杂的碳量子点（N,S-CQDs）及稳定性良好的金纳米团簇（BSA-Au NCs）,构建了N,S-CQDs@BSA-Au NCs比率荧光传感器,用于连续测定Ce⁴⁺和AA。当加入Ce⁴⁺后,BSA-Au NCs被Ce⁴⁺氧化,吸引BSA-Au NCs聚集成更大的颗粒,由于聚集诱导发射（AIE）效应,其荧光增强,因此构建了一个用于Ce⁴⁺检测的“打开”型近红外荧光传感平台。随后,当加入AA后,由于Ce⁴⁺的强氧化性对AA具有很强的亲和力,从而使BSA-Au NCs表面的Ce⁴⁺脱附,导致其荧光强度降低,开发了基于Ce⁴⁺介导的N,S-CQDs@BSA-Au NCs“关闭”型近红外荧光传感策略检测AA。结果表明,该基于“关-开-关”检测机理的比率荧光传感器在最优条件下,F₄₂₉/F₆₉₂与Ce⁴⁺浓度之间存在良好的线性关系,最低检测限为0.12μM;N,S-CQDs@BSA-Au NCs/Ce⁴⁺加入AA后,F₄₂₉/F₆₉₂与不同浓度的AA在1～10μM范围内也呈现良好的线性关系,最低检测限为0.19μM。且对一些可能共存的物质做了相关的干扰探究,实现该比率荧光传感器对Ce⁴⁺、AA的选择性识别和快速检测。更多还原

【Abstract】 In recent years,fluorescence analysis based on fluorescence CQDs has been widely used in biomedicine,environmental monitoring and other fields because of its high sensitivity,fast and simple.Based on CQDs,four kinds of fluorescence probes were prepared for the fluorescence detection of CIP,NO₃^–,PO₄^3–,AA and Ce⁴⁺:1.Using glucose as carbon source,CQDs were prepared by hydrothermal method.Combined with the dual advantages of rare earth complex and ratio fluorescence sensor,CQDs/Eu³⁺ratio fluorescence sensor with high sensitivity was constructed for CIP detection.Under excitation at 395 nm,CQDs/Eu³⁺has a strong blue fluorescence peak at 459 nm,and a weak red fluorescence peak at 616 nm.When the CIP exists,the fluorescence intensity of CQDs at 459 nm is enhanced based on charge transfer and hydrogen bond interaction.The experimental conditions of CQDs and Eu³⁺ratio,response time and stability were optimized.The results showed that:The ratio fluorescence sensor has a specific ability to identify CIP,and the fluorescence intensity ratio(F₄₅₉/F₆₁₆)has a good linear relationship with different concentrations of CIP（0～7μM）,and the minimum detection limit of CIP is 0.3μM,which is successfully used for accurate and sensitive detection of CIP.2.The Ui O-66-NH₂@Y-CQDs ratio fluorescence sensor was constructed by combining Ui O-66-NH₂ emitting blue fluorescence with Y-CQDs emitting yellow fluorescence by hydrothermal method,which was used for highly selective NO₃^–detection.The optical properties of Ui O-66-NH₂ were characterized by XRD,FT IR,SEM and TEM.When NO₃^–concentration changes,the fluorescence of Ui O-66-NH₂ is enhanced due to the weakening of LMCT effect.In addition,the effect of NO₃^–and Y-CQDs promoted charge transfer,leading to the fluorescence quenching of Y-CQDs,which changes the intensity of blue fluorescence at 413nm and yellow fluorescence at 564 nm were enhanced and weakened with the increase of NO₃^–concentration,respectively.The results show that:Under optimal conditions,F₄₁₃/F₅₆₄ showed a good linear relationship with NO₃^–in the concentration range of 1～10μM,with the lowest detection limit of 0.85μM.Moreover,the interference of some possible co-existing substances was investigated,which was successfully used for high sensitivity detection and selective identification of NO₃^–.3.High fluorescence CQDs were synthesized by hydrothermal method and encapsulated in ZIF-8.According to the SOS of ZIF-8 and the fluorescence of CQDs,CQDs@ZIF-8 ratio fluorescence sensor was constructed for the detection of PO₄^3–.The structure and morphology of the composite were analyzed by XRD,FT IR,SEM and TEM,and the fluorescence properties were analyzed by fluorescence spectrum.After adding PO₄^3–,it would react selectively with Zn²⁺in ZIF-8,resulting in the cracking of ZIF-8 to release CQDs,resulting in the fluorescence recovery of CQDs and the reduction of SOS intensity.The results show that the linear relationship between F₄₃₇/S₇₃₂ and PO₄^3–is good in the concentration range of 1～40μM under optimal conditions,and the lowest detection limit is 0.23μM.The interference of some possible co-existing substances has been investigated,and it has been successfully used for the rapid detection and selective recognition of PO₄^3–.4.N,S-CQDs and stable BSA-Au NCs were synthesized by hydrothermal method,and the N,S-CQDs@BSA-Au NCs ratio fluorescence sensor was constructed for the continuous determination of Ce⁴⁺and AA.When Ce⁴⁺was added,BSA-Au NCs were oxidized by Ce⁴⁺,which attracted BSA-Au NCs to aggregate into larger particles.The fluorescence of BSA-Au NCs was enhanced due to the AIE effect.Therefore,a"turn-on"near-infrared fluorescence sensor platform for Ce⁴⁺detection was constructed.Subsequently,when AA was added,Ce⁴⁺was desorbated on BSA-Au NCs surface due to its strong affinity for AA due to its strong oxidation,resulting in reduced fluorescence intensity.A Ce⁴⁺mediated N,S-CQDs@BSA-Au NCs"turn-off"type near infrared fluorescence sensing strategy was developed to detect AA.The results show that the ratio fluorescence sensor based on the"off-on-off"detection mechanism has a good linear relationship between F₄₂₉/F₆₉₂ and Ce⁴⁺concentration under optimal conditions,and the lowest detection limit is 0.12μM.N,S-CQDs@BSA-Au NCs/Ce⁴⁺added AA,F₄₂₉/F₆₉₂ also showed a good linear relationship with different concentrations of AA in the range of 1～10μM,and the lowest detection limit was 0.19μM.The interference of some possible co-existing substances was explored to realize the selective recognition and rapid detection of Ce⁴⁺and AA by the ratio fluorescence sensor.更多还原