Robust, sensitive and facile method for detection of F−, CN− and Ac− anions

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Vol. 186; pp. 8 - 16
• Main Authors: Madhusudhana Reddy, P., Hsieh, Shih-Rong, Chen, Jem-Kun, Chang, Chi-Jung, Kang, Jing-Yuan, Chen, Chih-Hsien
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 05.11.2017
• Subjects: Anions; Colorimetric; Naked eye; Sensor; Test stripes; Naked eye; Test stripes; Anions; Colorimetric; Sensor
• ISSN: 1386-1425; 1873-3557
• DOI: 10.1016/j.saa.2017.06.004

Sensing of F−, CN− and Ac− is important from the viewpoint of both medically and environmentally. Particularly, sensing of the anions in 100% water by a colorimetric chemical sensor is a highly difficult task as water molecules interfere the sensing mechanism. In this regard, sensor R1, having azo and nitrophenyl groups as signaling units and thiourea as a binding site was prepared. This sensor exclusively detected CN− ion over other testing anions in 30% aq. DMSO solution by exhibiting distinct spectral and visual color changes. However, in 15% aq. DMSO solution, R1 exhibited obvious spectral and color changes in response to F−, CN− and Ac−. On the other hand, we have also designed sensor, R2, having same signaling units of R1, but a different binding site of urea group. Surprisingly, in contrast to R1, R2 exhibited obvious spectral and color changes in 5% aq. DMSO solution only. Further, economically viable “test stripes” were prepared in a facile mode to detect the CN− in 100% aqueous solution. Such stripes can serve as a practical colorimetric probe for “in the field” detection of the ions and thus avoid additional expensive equipment. [Display omitted] •Colorimetric responses of R1 to anions in DMSO, DMSO-water and water were visible to the naked eye.•Simple, rapid, and cost effective paper “test stripes” were prepared to monitor the CN− in 100% water.•Sensor R1 showed excellent selectivity for F−, CN− and Ac− over other typical interferences anions.•The sensing abilities of the sensors were tuned by changing the nature of the binding sites.