A Colorimetric and Fluorescent Probe Based on Michael Acceptor Type Diketopyrrolopyrrole for Cyanide Detection.

A new probe 1 was synthesized by incorporating an α,β-unsaturated ketone to a diketopyrrolopyrrole fluorophore. The probe exhibited a selective and sensitive response to cyanide against other anions. Addition of CN- aqueous solution to 1 resulted in a rapid color change from pink to light yellow together with a blue shift from 518 to 421 nm, while other anions did not induce any significant color change. Furthermore, the Michael addition of cyanide to 1 elicited 98% fluorescence quenching at 608 nm, which constituted the fluorescence signature for cyanide detection. The detection limit was 0.67 μM using the fluorescence spectra changes, which was far lower than the WHO guideline of 1.9 μM. Moreover, 1-based test strips could successfully detect CN- solutions.