New Fluorescent and Colorimetric Chemosensor for Detection of Cyanide with High Selectivity and Sensitivity in Aqueous Media

A fluorescent and colorimetric chemosensor for detection of cyanide ion based on a styryl quinoline derivative has been designed and synthesized. The chemosensor ( E )-2-(4-mercaptostyryl)quinolin-8-ol L showed high selectivity for detection of cyanide over other anions such as F¯, Cl¯, Br¯, I¯, NO 3 ¯, SCN¯, N 3 ¯, ClO 4 ¯, H 2 PO 4 ¯, AcO¯, HCO 3 ¯, SO 4 2 ¯ and HSO 4 ¯in aqueous solution. The chemosensor L displayed an immediate visible and fluorescence changes from nearly colorless to orange and greenish-blue to brick-red upon addition of cyanide ion respectively. It is more likely, these distinct changes can be attributed to hydrogen bonding interaction between phenol group and cyanide anion leading to a 1:1 binding stoichiometry following with deprotonation of phenol group. The detection limit for chemosensor L toward CN¯ was 2.73× 10 −8 M. Thus, the chemosensor can be used efficiently and selectively for detection and monitoring of small amounts of cyanide ion in aqueous media.