采用水热法合成了一种SnO2量子点, 对其合成条件(如pH、温度、时间等)进行了优化, 并使用红外光谱、X粉末衍射、粒度分析仪、荧光光谱仪等手段对量子点的物化和光学性能进行了表征。实验结果显示, 合成的SnO2量子点分散均匀、粒径为5 nm左右; 在310 nm波长光激发下, 其最强发射峰位于415 nm, 且表现出良好的光学稳定性。在Fe3+存在时, SnO2量子点的荧光被猝灭, 而Fe2+对SnO2量子点的荧光没有影响, 利用抗坏血酸(AA)的还原性, 将Fe3+还原成Fe2+, 猝灭的SnO2量子点荧光恢复, 当AA浓度为500 μmol·L-1时, SnO2荧光恢复率达到95.88%, 其他氨基酸基本没有响应。基于此, 构建了一种“off-on”荧光探针用于抗坏血酸灵敏检测。

Using the stannous chloride as raw materials, we synthesized a SnO2 quantum dots by the means of hydrothermal method in this paper. The synthesis conditions such as pH, temperature, as well as time were optimized, and the FT-IR, XRD, Malvern Zetasizer Nano ZS90, FL-4600 fluorescence spectrophotometer etc. were utilized for the physicochemical and optical properties characterization of SnO2 quantum dots. The experimental result shows that the size of SnO2 quantum dots is about 5 nm, when excited with 310 nm light, the maximum emission peak of SnO2 quantum dots locats at 415 nm. In the presence of Fe3+, the fluorescence of SnO2 quantum dots is quenched, while the Fe2+ has no affection on the fluorescence of SnO2. Utilizing the reduction of ascorbic acid (AA), the Fe3+ ions can be reduced to Fe2+, resulting in the fluorescence restore efficiently. When the concentration of AA is 500 μmol·L-1, the fluorescence recovery can reach to 95.88%. Based on this, we constructed a novel off-on fluorescence probe based on SnO2 quantum dots for the sensitive detection of AA.