A New Azomethine Chemosensor for Naked-Eye Detection of CN− and AcOˉ: Application to Determination of Cyanide in Some Agro-Products and Poisoned Human Blood Samples

A new symmetrical azomethine probe, H₂L, has been synthesized via a condensation reaction of N, N´-Ethylene bis (3-formyl-5-methyl salicylaldimine), with Isonicotinic hydrazide in EtOH. The anion recognition studies exhibited that H₂L acts as a chemosensor for the detection of CN⁻ and AcO⁻ in pure DMSO and DMSO/H₂O 90:10(V/V) media over other basic anions such as F⁻, Cl⁻, Br⁻, I⁻, N₃⁻, SO₄²⁻, SO₃²⁻, PO₄³⁻, H₂PO₄⁻, HSO₄⁻, NO₂⁻, and NO₃⁻. The ability of the H₂L for rapid colorimetric sensing of CN⁻ and AcOˉ was studied using UV–Vis, and ¹H NMR titration methods. The detection limits of H₂L toward CN⁻ and AcO⁻ in the semi-aqueous medium were found to be 2.12 and 2.63 μM, respectively, which are lower than the LOD of some existing azomethine probes. Effectively, H₂L was used to qualitatively and quantitatively detect cyanide ions in the human-poisoned blood and some of the agro-products containing cyanogenic samples without relying on expensive instruments.