A Turn-On Fluorescent Chemosensor for Cyanide Ion Detection in Real Water Samples.

We have designed and synthesized a novel simple colorimetric fluorescent probe with aggregation-induced emission (AIE) properties. Probe 5-(4-(diphenylamine)phenyl) thiophen-2-formaldehyde exhibited a turn-on fluorescent response to cyanide ion (CN), which induces distinct visual color changes. Probe exhibited a highly selective and sensitive ratiometric fluorescence response for the detection of CN over a wide pH range (4-11) and in the presence of common interferents. The linear detection of CN over the concentration range of 4.00-38.00 µM ( = 0.9916, RSD = 0.02) was monitored by UV-Vis absorption spectrometry (UV-Vis) with the limit of detection determined to be 0.48 µM. The linear detection of CN over the concentration range of 8.00-38.00 µM was examined by fluorescence spectrophotometry ( = 0.99086, RSD = 0.031), and the detection limit was found to be 68.00 nM. The sensing mechanisms were confirmed by H NMR spectroscopic titrations, X-ray crystallographic analysis, and HRMS. Importantly, probe was found to show rapid response, high selectivity, and sensitivity for cyanide anions in real water samples, over the range of 100.17∼100.86% in artificial lake water and 100.54∼101.64% in running water by UV-Vis absorption spectrometry, and over the range of 99.42∼100.71% in artificial lake water and 100.59∼101.17% in running water by fluorescence spectrophotometry. Importantly, this work provides a simple and effective approach which uses an economically cheap and uncomplicated synthetic route for the selective, sensitive, and quantitative detection of CN ions in systems relevant to the environment and health.