Ultrahigh-sensitivity vinyl-COF fluorescent sensor for trace organic arsenic detection

Area of Science:

• Materials Science
• Environmental Chemistry
• Analytical Chemistry

Background:

• Organic arsenic feed additives like roxarsone (ROX) pose significant environmental and human health risks.
• Effective detection methods are crucial for monitoring and mitigating ROX contamination.

Purpose of the Study:

• To synthesize a novel fluorescent covalent organic framework (COF) for ultrahigh sensitivity detection of roxarsone (ROX).
• To investigate the sensing mechanism and performance of the synthesized COF for ROX detection.

Main Methods:

• Alkali-catalyzed reaction between 2, 3, 5, 6-tetramethylpyrazine (TMP) and terephthalaldehyde (TPA) to synthesize COF-TMP.
• Characterization of COF-TMP's properties, including porosity and fluorescence.
• Fluorescence-quenching titration experiments to determine the limit of detection (LOD) for ROX.

Main Results:

• COF-TMP, a pyrazine-cored fluorescent COF nanosheet, was successfully synthesized.
• COF-TMP exhibits high porosity, strong fluorescence, and abundant (E)-2-styrylpyrazine (SPA) groups.
• Achieved an ultra-low LOD of 0.015 ppb for ROX detection, surpassing existing sensors.
• Identified a static quenching mechanism responsible for the high detection capability.

Conclusions:

• COF-TMP is a highly effective fluorescent sensor for sensitive and selective ROX detection.
• The study presents a novel pyrazine-based fluorescent COF with potential applications in environmental pollution management.
• This research contributes to developing advanced materials for detecting harmful contaminants.