A reversible colorimetric chemosensor for "Naked Eye" sensing of cyanide ion in semi-aqueous solution

A new and simple receptor HL derived from quinoline-2-carbaldehyde and 2,4-dinitrophenylhydrazine was synthesized and explored as a colorimetric sensor for cyanide ion in DMSO/H2O (7: 3, v/v) medium. Addition of cyanide ion to HL resulted in a color change from yellow to wine red with a significant bathochromic shift (similar to 125 nm) in the absorption maxima, which makes naked eye detection possible. The experimental results reveal that the formation of anionic species from deprotonation of the hydrazone N-H moiety by CN-is responsible for the spectral changes. The sensor exhibits high selectivity and sensitivity for CN-ion and the detection limit were found to be 0.37 x 10(-6) M. Moreover, the HL-CN-complex was reversibly bound and HL could be recovered by treatment with Ag+ or Cu2+ and reused without loss of sensing ability. Finally, the use of a test strip of probe HL to detect cyanide was reported. (C) 2017 Elsevier B.V. All rights reserved.