Faculty of Materials Science and Chemical Engineering , Ningbo University , Ningbo 315211 , Zhejiang , China.
Institute for Superconducting & Electronic Materials, School of Mechanical, Materials and Mechatronics Engineering , University of Wollongong , Wollongong , New South Wales 2522 , Australia.
Anal Chem. 2019 Apr 2;91(7):4845-4851. doi: 10.1021/acs.analchem.9b00493. Epub 2019 Mar 14.
The development of simple, rapid-response sensors for water detection in organic solvents is highly desirable in the chemical industry. Here we demonstrate a unique luminescence water sensor based on a dual-emitting europium-organic framework (Eu-MOF), which is assembled from a purposely selected 2-aminoterephthalic acid ligand with responsive fluorescence inherent in its intramolecular charge transfer (ICT) process. This ICT process can be rapidly switched-on in the presence of water owing to its ability to boost and stabilize the ICT state. In contrast, the Eu emission within the framework is insensitive to water and can serve as a reference, thus enabling highly sensitive water detection in a turn-on and ratiometric way. In addition, the significant ratiometric luminescence response induced by water makes Eu-MOF undergo a distinct change of emitting color from red to blue, which is favorable for visual analysis with the naked eye. Sensitive determination of water content (0.05-10% v/v) in various organic solvents is achieved in multiple readouts including ratiometric emission intensity, emission color, or the Commission Internationale de l'Eclairage (CIE) chromaticity coordinate. The present Eu-MOF sensor featuring high sensitivity and reusability, self-calibration, simple fabrication and operation, and capability for real-time and in situ detection is expected to have practical applications in water analysis for industrial processes.
在有机溶剂中检测水的简单、快速响应传感器的发展在化学工业中是非常需要的。在这里，我们展示了一种基于双发射铕-有机骨架（Eu-MOF）的独特发光水传感器，该骨架由特意选择的 2-氨基对苯二甲酸配体组装而成，其分子内电荷转移（ICT）过程具有响应荧光固有性质。由于其增强和稳定 ICT 态的能力，在存在水的情况下，这种 ICT 过程可以迅速开启。相比之下，骨架内的 Eu 发射对水不敏感，可以作为参考，从而能够以开启和比率方式实现对水的高灵敏度检测。此外，水诱导的显著比率发光响应使 Eu-MOF 发射颜色从红色变为蓝色，这有利于肉眼进行可视化分析。通过包括比率发射强度、发射颜色或国际照明委员会（CIE）色度坐标在内的多种读取方式，在各种有机溶剂中实现了对含水量（0.05-10% v/v）的灵敏测定。本研究中的 Eu-MOF 传感器具有高灵敏度、可重复使用性、自校准、简单的制造和操作以及实时和原位检测能力，有望在工业过程中的水分析中得到实际应用。
