Development of a highly selective and colorimetric probe for simultaneous detection of Cu2+ and CN- based on an azo chromophore

In this work, a highly selective and colorimetric probe based on an azo chromophore was designed and synthesized for simultaneous detection of Cu2+ and CN- in aqueous acetonitrile solution. The designed probe (S4) includes the azo unit ( N=N) and the quinazolinone unit as the fluorophore and a binding site, respectively. The probe S4 displayed remarkable colorimetric responses from yellow to orange and yellow to green in the presence of CN- and Cu2+, respectively. Meanwhile, the sensing details were evaluated using UV-vis spectroscopy. The mechanisms of CN- and Cu2+ interactions with probe S4 has been investigated using the FT-IR, H-1 NMR titration experiments and Job's plot. In addition, utilizing probe S4, cyanide ion in real industrial samples can be rapidly recognized and quantitated by the naked eye. The limit of detection (LOD) for S4 toward CN- and Cu2+ was found to be 2.7 mu M and 14.9 mu M respectively. Furthermore, Job's plot based on spectroscopic data showed one-to-one stoichiometry for the interaction of Cu2+ ions with probe S4. The results indicate that S4 is a simple and useful probe for simultaneous selective sensing of CN- and Cu2+ ions in experimental and real industrial samples. (C) 2017 Elsevier B.V. All rights reserved.