A rapid and sensitive colorimetric method for the detection of cyanide ions in aqueous samples

Abstract Cyanide is a highly toxic environmental pollutant that bind to metalloenzymes such cytochrome C oxidase causing respiratory arrest and death in aquatic and terrestrial organisms. Here, a recognition solution for cyanide detection has been formulated that was further used for the development of chromogenic test-strips. The interaction of the recognition solution with potassium cyanide produces a colorimetric response quantifiable at 586 nm as well as a distinctive fluorescence spectrum with emission at 620 nm. Potassium cyanide was identified in aqueous samples using standard spectrophotometric method with a limit of detection of 0.27 ± 0.1 ppm. The samples collected from canal, tannery and textile industry effluents tested with the spectrophotometric method showed cyanide contamination of 0.77 ppm, 2.56 ppm and 2.71 ppm, respectively. The chromogenic test-strip showed a limit of detection of 1 ppm with the standards aqueous and environmental samples. The developed method and test-strips are selective for cyanide and the response is unaffected by the presence of interferents such as Cl − , Br − , I − , HCO − , PO 3 − , SO 2 − and AcO − in the matrix. The developed chromogenic test-strips can be used in point-of-use applications where sophisticated equipments are not available.