A fluorescent turn-on probe based on benzo [e] indolium for cyanide ion in water with high selectivity.

A highly selective fluorescent turn-on probe for CN(-) bearing a benzo [e] indolium group as a fluorophore and binding site was reported. The detection of CN(-) was performed via the nucleophilic attack of CN(-) toward the benzo [e] indolium group of the probe, resulting in a prominent fluorescence enhancement and an obvious color change. The probe shown a highly selectivity in water and could be performed in a range of pH value between 6 and 9. The detection limit was 4.6 × 10(-8) M, which could be detected CN(-) in drinking water. A simple paper test strip system for the rapid monitoring of CN(-) was developed.