Cadmium ions have been of crucial concern due to the high biological toxicity and serious environmental risks. Various fluorescent Cd-sensitive probes have been reported with improved sensing properties, but still severely suffer from poor stability and insufficient selectivity. In this work, a stable fluorescent probe based on silica encapsulated quantum dots (QDs) have been developed for rapid, sensitive and selective detection of cadmium ion. To improve fluorescence stability, the strategy of mesoporous silica encapsulation was adopted, in which the mesoporous silica shell offers numerous channels for Cd²⁺. Further, the Forster Resonance Energy Transfer (FRET) system, where QDs@mSiO₂ and rhodamine B (RB) are used as donors and acceptors respectively, has been constructed, in which the mesoporous silica shell also serves as spacers with tunable thickness for controlling the QD-RB distance. Under optimal conditions, the probes possess a sensitive fluorescence response with a detection limit of 1.25 μM. Visual detection can be realized by the obvious fluorescence changes of the FRET system. In addition, the FRET system shows promising sensing performances both in tap water samples and rice-washed water samples, confirming a great potential for practical application.

由于高生物毒性和严重的环境风险，镉离子一直是至关重要的问题。据报道，各种荧光 Cd 敏感探针具有改进的传感特性，但仍然严重存在稳定性差和选择性不足的问题。在这项工作中，已经开发了一种基于二氧化硅封装的量子点 (QD) 的稳定荧光探针，用于快速、灵敏和选择性地检测镉离子。为了提高荧光稳定性，采用了介孔二氧化硅封装的策略，其中介孔二氧化硅壳为 Cd ²⁺提供了许多通道。此外，Forster 共振能量转移 (FRET) 系统，其中 QDs@mSiO ₂和罗丹明 B (RB) 分别用作供体和受体，已经构建，其中介孔二氧化硅壳还用作具有可调厚度的间隔物，用于控制 QD-RB 距离。在最佳条件下，探针具有与1.25的检测极限的敏感荧光响应μ可通过FRET系统的明显的荧光变化来实现M.视觉检测。此外，FRET 系统在自来水样品和淘米水样品中均显示出良好的传感性能，证实了其在实际应用中的巨大潜力。