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Covalent Organic Framework Functionalized with 8-Hydroxyquinoline as a Dual-Mode Fluorescent and Colorimetric pH Sensor

2018; American Chemical Society; Volume: 10; Issue: 18 Linguagem: Inglês

10.1021/acsami.8b05484

1944-8252

Long Chen, Linwei He, Fuyin Ma, Wei Liu, Yaxing Wang, Mark A. Silver, Lanhua Chen, Lin Zhu, Daxiang Gui, Juan Diwu, Zhifang Chai, Shuao Wang,

Luminescence and Fluorescent Materials

Real-time and accurate detection of pH in aqueous solution is of great significance in chemical, environmental, and engineering-related fields. We report here the use of 8-hydroxyquinoline-functionalized covalent organic framework (COF-HQ) for dual-mode pH sensing. In the fluorescent mode, the emission intensity of COF-HQ weakened as the pH decreased, and also displayed a good linear relationship against pH in the range from 1 to 5. In addition, COF-HQ showed discernible color changes from yellow to black as the acidity increased and can be therefore used as a colorimetric pH sensor. All these changes are reversible and COF-HQ can be recycled for multiple detection runs owing to its high hydrolytical stability. It can be further assembled into a mixed matrix membrane for practical applications.