Song Jinping, Ma Qi, Liu Yequn, Guo Yong, Feng Feng, Shuang Shaomin
College of Chemistry and Environmental Engineering, Institute of Applied Chemistry, Shanxi Datong University Datong Shanxi 037009 China
Analytical Instrumentation Center, State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences Taiyuan 030001 China
RSC Adv. 2019 Nov 26;9(66):38568-38575. doi: 10.1039/c9ra07030c. eCollection 2019 Nov 25.
In this study, dual-emission carbon dots (D-CDs) are synthesized a simple one-step solvothermal treatment of red tea. The obtained D-CDs are characterized by XPS, IR, TEM, XRD, fluorescence and UV-vis spectroscopy techniques. It is found that D-CDs present a strong red fluorescence emission peak at 671 nm and weak blue fluorescence emission peak at 478 nm under the excitation wavelength of 410 nm. The unique dual-emission properties of D-CDs provide great opportunities in ratiometric fluorescence sensing applications. The results show that Cu ions can quench the fluorescence of the red emission band of D-CDs effectively, resulting in the disappearance of red fluorescence ultimately. Upon the addition of Al ions, the fluorescence of blue emission band at 478 nm grows apparently, and the fluorescence color transforms gradually from red to orange, then to yellow-green. Based on these findings, a novel ratiometric fluorescence and colorimetric dual mode nanosensor is developed for simultaneous detection of Cu and Al ions. Regarding Cu ions, the fluorescent detection linear range is 0.1-50 μM with detection limit of 0.1 μM, and the colorimetric detection limit is estimated as 25 μM. With regard to Al ions, the fluorescent detection linear range is 0-20 μM and 25-100 μM with detection limit of 0.5 μM, and the colorimetric detection limit is 20 μM. Furthermore, the fluorescence response mechanisms of Cu and Al ions were discussed detailed. To the best of our current knowledge, this will be the first research work on the simultaneous determination of Cu and Al using D-CDs as fluorescent probes.
在本研究中，通过对红茶进行简单的一步溶剂热法处理合成了双发射碳点（D-CDs）。采用XPS、红外光谱（IR）、透射电子显微镜（TEM）、X射线衍射（XRD）、荧光光谱和紫外可见光谱技术对所得的D-CDs进行了表征。结果发现，在410nm激发波长下，D-CDs在671nm处呈现出强的红色荧光发射峰，在478nm处呈现出弱的蓝色荧光发射峰。D-CDs独特的双发射特性为比率荧光传感应用提供了巨大机遇。结果表明，铜离子能够有效猝灭D-CDs红色发射带的荧光，最终导致红色荧光消失。加入铝离子后，478nm处蓝色发射带的荧光明显增强，荧光颜色逐渐从红色转变为橙色，再转变为黄绿色。基于这些发现，开发了一种新型的比率荧光和比色双模式纳米传感器，用于同时检测铜离子和铝离子。对于铜离子，荧光检测线性范围为0.1-50μM，检测限为0.1μM，比色检测限估计为25μM。对于铝离子，荧光检测线性范围为0-20μM和25-100μM，检测限为0.5μM，比色检测限为二十μM。此外，还详细讨论了铜离子和铝离子的荧光响应机制。据我们目前所知，这将是首次使用D-CDs作为荧光探针同时测定铜和铝的研究工作。
