A pH-regulated fluorescence covalent organic framework for quantitative water content detection in methanol.

In this paper, we designed and synthesized a two-dimensional fluorescent covalent organic framework (TAPB-DMTP-COF) for the precise determination of H ₂ O content in methanol. The COF was synthesized using two typical monomers by grinding method, which significantly reduced the synthesis time. By adjusting the pH value of the COF suspension to 4.0, the portion of the COF material structure is disrupted, thereby mitigating π-π stacking and resolving the aggregation-caused quenching (ACQ) effect. Consequently, the non-fluorescent TAPB-DMTP-COF exhibited blue-purple fluorescence emission in methanol. At the same time, it is observed that in the presence of H ₂ O, there is a red shift in the maximum fluorescence emission peak of TAPB-DMTP-COF, which correlates with the H ₂ O content within a specific range. Notably, this redshift demonstrates a linear relationship with H ₂ O content from 4% to 80% in methanol. Our work presents novel insights for efficient analysis and detection of H ₂ O content in methanol and could be used for H ₂ O detection in other organic solvents.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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