Using Smartphone APP To Determine the CN Concentration Quantitatively in Tap Water: Synthesis of the Naked-Eye Colorimetric Chemosensor for CN and Ni Based on Benzothiazole.

A naked-eye colorimetric chemosensor based on benzothiazole could recognize CN effectively. When interacted with CN in the aqueous solution, the obvious color change of the solution was directly observed by the naked eye. Other anions did not cause any interference. It is interesting that could also discriminate Ni from other cations, and the possible interaction mode between them was verified based on the Job's plot, H nuclear magnetic resonance titration, infrared , electrospray ionization mass spectrometry, scanning electron microscopy analysis, and density functional theory calculation methods. As a result, it is clear that the mode of action between and CN was different from that between and Ni. Meanwhile, the limit of detection of toward CN and Ni was calculated to be 1.7 × 10 or 7.4 × 10 M, respectively. In addition, CN was recognized qualitatively by a test paper and silica gel plates made from . was able to detect CN in tap water quantitatively, rapidly, and on-site by the use of a smartphone APP. All results implied that has certain prospects for practical application to identify CN in water.