Fluorogenic detection of cyanide ions in pure aqueous media through an intramolecular crossed-benzoin reaction: limitations unveiled and possible solutions†‡

Reaction-based fluorogenic sensing of lethal cyanide anions in aqueous matrices remains a big challenge. We have revisited the reported approach about an intramolecular crossed-benzoin reaction leading to the release of a phenol-based fluorophore. Fluorescence assays and RP-HPLC-MS analyses have helped us to highlight its limitations related to poor aqueous stability of probes and impossibility to achieve molecular amplification despite the assumed catalytic activation mechanism. Traceless cleavable linker strategies were considered to obtain usable cyanide-responsive chemodosimeters and statistical analyses of fluorescence data have been conducted in depth to accurately delineate their sensing performances, especially the limit of detection (LOD).