Spectrophotometric determination of cyanide ions with a new colorimetric chemosensor

In this study, a new chemosensor 5-chloro-2-(2'-hydroxyphenyl)benzothiazole (Cl-HPBT) was used for the determination of cyanide (CN-) ions in water samples. The sensing properties of Cl-HPBT for cyanide determination were investigated by UV-Vis absorption spectroscopy. The chemosensor exhibited good selectivity to cyanide ions among all studied anions (F-, Cl-, Br-, NO3-, SO42-, SCN-, I-, C2O42-, HPO42-, CrO42-, CO32-, CH3COO-) The chemosensor color changed from colorless to yellow in the presence of CN-. The interaction mechanism of Cl-HPBT and CN- was confirmed by NMR experiments and the stoichiometric ratio was obtained at 1:1 from Job's method. The binding constant (Ka) value was found to be 2,9 x 103 M-1 by the Benesi-Hildebrand equation. The limit of detection (LOD) and the limit of quantification of the chemosensor-based method for CN- was determined as 5,4 x 10-7 M (0,54 µM) and 1,8 x 10-6 M (1,8 µM) respectively. The determination of CN- in various water samples was successfully applied by using this chemosensor-based method.