A Novel and Reactive Fluorescent "Turn-on" Probe Based on Benzimidazole Derivative for Selective CN- Detection

A novel fluorescent probe L based on benzimidazole derivative for selective CN- detection was designed and synthesized, and its structure was identified by spectral analysis. In DMSO/H2O (v/v=7 : 3, pH=9) solvent system, the fluorescence intensity for L enhances and the color change from yellow to colorless and purple was immediately observed at 426 nm, but there was no obvious color change when other anions instead of CN- was added to the system. The mechanism on CN- recognition was also studied by H-1 NMR, IR, MS analysis and theoretical calculations. The probe L for CN- detection exhibited high sensitivity, and the molar ratio and lowest detection limit was 1 : 1 and 8.2x10(-7) mol L-1, respectively. In addition, the probe L could be successfully applied to the detection of CN- in bitter almond, and was also used as a test paper, which indicated that the probe L might conveniently carried out the quick identification and detection of cyanide ion in the environment and food samples through its fluorescent color change under UV lamp.