Fluorescein Based Three-channel Probe for the Selective and Sensitive Detection of CO₃^2- Ions in an Aqueous...

We have constructed a novel fluorescein-based fluorescent chemosensor, FL-In, functionalised with an indole moiety and capable of sensing by both the optical "turn-on" and electrochemical detection of carbonate ions (CO₃^2-) in aqueous media. The probe exhibits excellent selectivity and a low detection limit (0.27 µM) regarding carbonate ions by a possible coordination and hydrolysis reaction mechanism. The developed probe successfully detected CO₃^2- ions in different samples of water. Also, in a simple filter paper experiment, we documented its ability to allow the monitoring of CO₃^2- with the naked eye.