Detection of cyanide ions in aqueous solutions using cost effective colorimetric sensor

• Published in: Journal of hazardous materials 2017-07, Vol.334, p.93-103
• Main Authors: Reddy, P. Madhusudhana, Hsieh, Shih-Rong, Chang, Chi-Jung, Kang, Jing-Yuan
• Format: Article
• Language: English
• Subjects: Colorimetric; Cyanide; Naked eye; Sensing; Test stripes
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2017.04.001

[Display omitted] •Colorimetric responses of S1 to anions in DMSO, DMSO-water and water were visible to the naked eye.•Detection of CN̄ by S1 was monitored by means of UV-vis, fluorescence, and test stripes techniques.•The chlorine and benzoyl group can amplify the sensing performance of anthraquinone based sensors.•Simple, rapid, and cost effective paper “test stripes” of S1 can monitor the CN̄ in 100% water.•The S1 has an excellent sensitivity with the detection limits under micro molar concentrations. Cyanide (CN̄) is one of the most toxic material to the human and environment. It is very important to develop the diagnostic tools for the detection of CN̄ ions. Moreover, detection of the ions in an aqueous medium is a challenging task as water molecules interfere with the sensing mechanism. In this context, we prepared chemical sensor, S1, having anthraquinone as a signaling unit and thiourea as a binding site. This sensor exhibited distinct visual color and spectral changes in response to CN̄ ion over other testing anions in 50% aq. DMSO solution. However, in 20% aq. DMSO solution, S1 exhibited obvious spectral and color changes in response to CN̄, fluoride (F̄), acetate (Ac̄) and benzoate (Bz̄). Another sensor, S2, having a same signaling unit with that of S1, but a different binding site of urea group. In contrast to S1, S2 exhibited obvious spectral and color changes to F̄ in 2.5% aq. DMSO solution. NMR titration results suggested that the spectral and colorimetric responses were due to the formation of host-guest complex and deprotonation events. Finally, economically viable paper-based colorimetric “test stripes” of S1 were fabricated to detect the CN̄ ions in 100% aqueous solution.