An antimalarial drug, tafenoquine, as a fluorescent receptor for ratiometric detection of hypochlorite

Tafenoquine (TQ), a fluorescent antimalarial drug, was used as a receptor for the fluorometric detection of hypochlorite (OCl−). TQ itself exhibits a strong fluorescence at 476 nm, but OCl−-selective cyclization of its pentan-1,4-diamine moiety creates a blue-shifted fluorescence at 361 nm. This ratiometric response facilitates rapid, selective, and sensitive detection of OCl− in aqueous media with physiological pH. This response is also applicable to a simple test kit analysis and allows fluorometric OCl− imaging in living cells.