Fluorescent detection is a new spectroscopic measurement for ions sensing due to the advantages of real‐time determination with high selectivity, accuracy, and low cost. However, chemosensors based on fluorescent detection are usually determined by absolute intensity from a monochromatic emission signal, which is easy to be fluctuated by the external environment, especially for Fe³⁺ detection in complex fluids. Herein, we rationally design a dual‐emission Eu³⁺: CDs@ZIF‐8 to construct a ratiometric fluorescent sensor with self‐calibrating ability for Fe³⁺ determination. High efficient carbon dots (CDs) are embedded in europium ions (Eu³⁺)‐doped MOF by simple stirring preparation at room temperature. The label‐free ratiometric fluorescent probe (I_CDs@ZIF‐8/I_Eu) exhibits simultaneous blue and red emission under the same excitation at 365 nm. Remarkably, Eu³⁺: CDs@ZIF‐8 displays the superiority of high selectivity to Fe³⁺, which shows ratiometric fluorescence characteristics (I₀/I) in a range of 0‐6 μmol\L with a low limit of detection (LOD) of 0.897 μmol\L. Besides, the CDs‐MOF nanocomposite holds good aqueous dispersibility and low cytotoxicity, which shows great potential applications in medical aid including biological detection and clinical diagnosis.

中文翻译：

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将碳点嵌入Eu3 +掺杂的金属有机框架中，以进行无标记的Fe3 +离子比例荧光检测

荧光检测是一种用于离子感应的新型光谱测量方法，这归因于实时测定的高选择性，准确性和低成本优势。但是，基于荧光检测的化学传感器通常由来自单色发射信号的绝对强度确定，这很容易受到外部环境的影响，特别是对于复杂流体中的Fe ³⁺检测。本文中，我们合理设计了一种双发射Eu ³⁺：CDs @ ZIF-8，以构建具有自校准能力的Fe ³⁺测定的比例荧光传感器。高效碳点（CD）嵌入euro离子中（Eu ³⁺通过在室温下简单搅拌制备）即可掺入MOF。无标记比例荧光探针（I _{CDs @ ZIF-8} / I _Eu）在365 nm的相同激发下同时显示蓝色和红色发射。值得注意的是，Eu ³⁺：CDs @ ZIF-8表现出对Fe ³⁺的高选择性，在0-6μmol\ L范围内显示比例荧光特性（I ₀ / I），检测限低（ LOD）为0.897μmol\ L。此外，CDs-MOF纳米复合材料具有良好的水分散性和低细胞毒性，这在包括生物检测和临床诊断在内的医疗援助中显示出巨大的潜在应用。