Visual and reversible detection of cyanide ions in protic solvents by a novel colorimetric receptor

A novel colorimetric chemodosimeter for cyanide (CN⁻) and 1-allyl-4-[2-(4-hydroxyphenyl)ethenyl)]-quinolinium bromide (AHPEQB) was designed and synthesized by condensation and terminal N alkyl reaction. AHPEQB exhibited highly selective and sensitive recognition properties toward CN⁻ over other competing anions in ethanol, a protic solvent, with a 1:1 binding stoichiometry and a detection limit of 1.7 × 10⁻⁶ mol Lˉ1. AHPEQB also displayed rapid colorimetric response that could be readily observed by the naked eye and good reversibility. The sensing mechanism of the proposed chemodosimeter was studied by UV–Vis, 1H NMR titration, and comparison 1-allyl-4-[2-(4-acetoxyphenyl)ethenyl)]-quinolinium bromide (AAPEQB). The colorimetric chemodosimeter showed high accuracy in determining the concentration of CN⁻ in real water samples. Copyright © 2014 Elsevier Ltd. All rights reserved.