Rapid and highly selective relay recognition of Cu(II) and sulfide ions by a simple benzimidazole-based fluorescent sensor in water

To realize highly selective relay recognition of Cu2+ and sulfide ions, a simple benzimidazole-based fluorescent chemosensor (1) was designed and synthesized. Sensor 1 displays rapid, highly selective and sensitive recognition to Cu2+ in 100% water solution at pH 6.0. The in situ generated 1-Cu2+ complex solution exhibit a fast response and high selectivity toward sulfide anion via Cu2+ displacement approach. The detection limits of sensor 1 to Cu2+ and 1-Cu2+ complex to sulfide anion were estimated to be 3.5 × 10−7 M and 1.35 × 10−6 M, respectively. Proof-of-concept experiment results demonstrate that sensor 1 has potential utilities for Cu2+ and sulfide ion concentration evaluation in real water samples. This successive recognition feature of sensor 1 makes it has a potential utility for Cu2+ and sulfide anion detection in water.