红枣碳量子点“关-开”型荧光探针检测芦丁的研究

以红枣为原料，通过一步水热法合成了具有强烈荧光的碳量子点（CQDs），通过荧光光谱、紫外-可见光谱、红外光谱、X射线粉末衍射光谱对其发光特性进行了研究，并基于KMnO₄与CQDs形成无辐射复合体，构建了"关-开"型荧光探针用于芦丁的高灵敏度检测。实验发现，在pH=4.00的HAc-NaAc缓冲溶液中，KMnO₄的加入可使CQDs的荧光发生显著猝灭，体系的荧光信号处于"关闭"状态；加入芦丁后，由于KMnO₄更易与还原性药物芦丁发生反应，将KMnO₄从CQDs表面移除下来，使CQDs的荧光得以恢复，体系的荧光信号处于"打开"状态。对反应的机理进行初步探讨，考察了各种反应条件，在优化的实验条件下，CQDs荧光探针荧光恢复值ΔF与芦丁的浓度在2.5×10^-7~1.0×10^-5 mol/L范围内呈良好线性关系，方法检出限为1.5×10^-7 mol/L。该方法应用于样品中芦丁的测定，结果满意。

Synthesized of Carbon Quantum Dots from Red Dates and as A “Off-On” Fluorescence Probe for High Sensitive Detection of Rutin

A one-step hydrothermal method was developed for the preparation of carbon quantum dots(CQDs) with strong fluorescence by using red dates as precursors. The luminescence properties of the CQDs were studied by fluorescence spectroscopy, UV-Vis spectrum, transmission electron microscopy, infrared spectrum, X-ray powder diffraction spectroscopy. In pH=4.00 NaAc-HAc buffer solution, after potassium permanganate(KMnO₄) was added in CQDs solution, the fluorescence of CQDs was quenched, and the fluorescence signal of the system was in the "off" state. In the presence of rutin, the fluorescence of CQDs was recovered because KMnO₄ preferred to react with rutin, which results in the departure of KMnO₄ from the surface of the CQDs, and the fluorescence signal of the system was "open". The degree of recovery of CQDs fluorescence intensity was proportional to the rutin concentration, which provided a new method for the detection of rutin with high sensitivity and selectivity based on the fluorescence quenching-recovery properties of CQDs. The mechanism of fluorescence quenching of CQDs by KMnO₄ was studied, and the reaction conditions were optimized. Under optimal conditions, the recovered fluorescence of CQDs is linearly related with the rutin concentration in the range 2.5×10^-7-1.0×10^-5 mol/L, the detection limit is 1.5×10^-7 mol/L. The present method is applied for the detection of rutin in samples with satisfactory results.