A Highly Selective Sensor for Cyanide in Organic Media and on Solid Surfaces

• Published in: Sensors (Basel, Switzerland) Vol. 16; no. 3; p. 271
• Main Authors: Barare, Belygona, Babahan, Ilknur, Hijji, Yousef M, Bonyi, Enock, Tadesse, Solomon, Aslan, Kadir
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 24.02.2016; MDPI
• Subjects: anion sensing; Anions; Anions - isolation & purification; Blue shift; Carbocyanines - chemistry; chemical sensors; Chemistry; Chromatography; cyanide sensing; Cyanides; Cyanides - chemistry; Cyanides - isolation & purification; cyanine dyes; Dyes; Emission analysis; Fluorescence; Fluorescent Dyes - chemistry; Humans; Indoles - chemistry; IR-786; near-infrared fluorophores; optical sensors; Sensors; Solid state; Solid surfaces; Solvents; Solvents - chemistry; Spectrometry, Fluorescence; Water - chemistry; Water Pollutants, Chemical - chemistry; Water Pollutants, Chemical - isolation & purification; United States > US; Qatar; anion sensing; cyanide sensing; IR-786; optical sensors; near-infrared fluorophores; chemical sensors; cyanine dyes
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s16030271

The application of IR 786 perchlorate (IR-786) as a selective optical sensor for cyanide anion in both organic solution (acetonitrile (MeCN), 100%) and solvent-free solid surfaces was demonstrated. In MeCN, IR-786 was selective to two anions in the following order: CN(-) > OH(-). A significant change in the characteristic dark green color of IR-786 in MeCN to yellow was observed as a result of nucleophilic addition of CN(-) to the fluorophore, i.e., formation of IR 786-(CN), which was also verified by a blue shift in the 775 nm absorbance peak to 430 nm. A distinct green fluorescence emission from the IR-786-(CN) in MeCN was also observed, which demonstrated the selectivity of IR-786 towards CN(-) in MeCN. Fluorescence emission studies of IR-786 showed that the lower detection limit and the sensitivity of IR-786 for CN(-) in MeCN was 0.5 μM and 0.5 to 8 μM, respectively. The potential use of IR-786 as a solvent-free solid state sensor for the selective sensing and monitoring of CN(-) in the environment was also demonstrated. On solvent-free solid state surfaces, the sensitivity of the IR-786 to CN(-) in water samples was in the range of 50-300 μM with minimal interference by OH(-).