A "turn-on" fluorescent sensor based on three-component covalent organic framework for trace water detection.

Area of Science:

• Materials Science
• Chemical Engineering
• Analytical Chemistry

Background:

• Trace amounts of water (H2O) act as critical impurities in laboratory and industrial settings.
• The presence of H2O can significantly impact chemical reaction outcomes, including product yield and selectivity.
• Accurate detection of trace H2O is therefore essential for process control and product quality.

Purpose of the Study:

• To synthesize novel covalent organic frameworks (COFs) with controlled intramolecular charge transfer (ICT) and aggregate-induced emission (AIE) properties.
• To investigate the relationship between COF composition and their responsiveness to trace H2O.
• To develop a sensitive and selective fluorescent sensor for detecting trace H2O.

Main Methods:

• Synthesis of TFPT[X]-BMTH-COFs via amino-aldehyde condensation, varying TFPT content.
• Characterization of COFs for ICT and AIE properties.
• Fabrication and testing of a fluorescent H2O sensor using TFPT[67]-BMTH-COF.

Main Results:

• TFPT[X]-BMTH-COFs exhibited tunable ICT and AIE characteristics based on TFPT content.
• A sensor based on TFPT[67]-BMTH-COF demonstrated a wide linear detection range (0-0.5 wt%) for H2O.
• The sensor achieved a low detection limit of 0.00007 wt% for H2O.
• A portable fluorescent test paper was developed for visual H2O detection in honey and salt.

Conclusions:

• The developed TFPT[X]-BMTH-COFs offer a promising platform for sensitive H2O detection.
• The tunable fluorescence properties enable precise control over sensor performance.
• This work provides a foundation for creating advanced fluorescent probes for visual trace water detection.