A novel D-π-A triphenylamine-based turn-on colorimetric and ratiometric fluorescence probe for cyanide detection

A novel colorimetric fluorescent chemosensor TP1 with a D-π-A structure for the detection of (cyanide) CN− has been developed. TP1 is capable of showing high selectivity and sensitivity towards CN− over a wide range of other interfering anions. After reaction with CN−, TP1 shows a significant blue-shift of absorption peak from 514 to 437 nm, which induces color changes from amaranth to yellow. Non-fluorescent TP1 upon interaction with CN− exhibits a ca. 17-fold fluorescence enhancement at 551 nm, resulting in strong orange emission. The sensing mechanism of TP1 recognizes CN− which undergoes a nucleophilic addition reaction. Moreover, the detection limit of the probe TP1 towards CN− is 1.4 × 10−8 M, which is far lower than the WHO guideline of 1.9 μM cyanide for drinking water. In addition, the cell imaging experiments certify that TP1 can be successfully applied as a bioimaging agent for monitoring CN− in pheochromocytoma cell (PC12).