A simple fluorophore-imine ensemble for colorimetric and fluorescent detection of CN− and HS− in aqueous solution

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Vol. 229; p. 117974
• Main Authors: Lakshmi, P. Raja, Kumar, P. Saravana, Elango, Kuppanagounder P.
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 15.03.2020
• Subjects: Colorimetric; Cyanide; Fluorescent; Hydrogen sulfide; Sensing; Hydrogen sulfide; Fluorescent; Cyanide; Sensing; Colorimetric
• ISSN: 1386-1425; 1873-3557
• DOI: 10.1016/j.saa.2019.117974

Colorimetric and fluorescent detection of cyanide and hydrogen sulfide ions has been effected using a simple organic probe in H2O:DMSO (20:80, v/v) medium. The probe exhibits a colour change from pale-yellow to red upon addition of these analytes under normal light and fluorescent change from green to red under UV lamp. Other competitive ions show no observable colour or fluorescence change. The binding constants of cyanide and hydrogen sulfide ions with the probe determined using fluorescence titration data are found to be 2.1 × 104 and 1.6 × 104 M−1, respectively. The probe fluorimetrically detects the analytes in a wide pH range (4–10). 1H and 13C NMR studies suggest that the probe senses cyanide ion through deprotonation and nucleophilic addition mechanism and hydrogen sulfide ion via deprotonation mechanism. Detection limits of cyanide and hydrogen sulfide are determined to be 0.15 and 1 μM, respectively. The practical utility of the probe has been demonstrated by same dual mode detection of cyanide in food materials like bitter almond, cassava flour and sprouting potato. [Display omitted] •A simple imine based probe has been designed and synthesized.•The probe detects CN− and HS− selectively and sensitively.•The dual channel detection of CN− involves deprotonation and nucleophilic addition.•The LOD of CN− and HS− are 0.15 and 1 μM, respectively.•The probe successfully detects cyanide in food materials.