A Turn‐On Fluorescence Chemosensor for Cyanide in Aqueous Media Based on a Nucleophilic Addition Reaction

We synthesized a new cyanide (CN ^?) chemosensor CX based on a nucleophilic addition reaction prompted by cyanide ion, which could be used for highly selective and sensitive fluorescence turn‐on detection of cyanide in aqueous media. The CX showed selective fluorescence recognition for CN ^?, the miscellaneous competitive anions (F^?, Cl^?, Br^?, I^?, AcO ^?, H₂PO₄^?, HSO₄^?, ClO₄^?, S^{2 ?}, PO₄^3?, CO₃^2? and SCN ^?) did not lead to any significant interference. The detection limit of the sensor towards CN ^? is 1.15 × 10^?7 mol?L^?1. The sensor has been successfully applied to estimate the cyanide ion in seeds of cherries. Test strips based on CX were fabricated, which could be used as a convenient and efficient CN ^? test kit to detect CN ^? in aqueous solution for “in‐the‐field” measurement.