Novel chromogenic selective sensors for aqueous cyanide ions under high water content and real sample analysis

Abstract

Novel chromogenic receptors (R1–R2) containing anthraquinone as the signalling unit and imidazole as the binding unit were designed to enhance the sensing action in an aqueous medium. R1 showed an obvious color change from yellow to red for aqueous CN⁻ ions among other anions, even under 8 : 2 H₂O : DMSO medium. R2 showed good sensitivity with micromolar detection limit for cyanide ions in aqueous media. The binding stoichiometry of the complexes formed by cyanide ions with receptors was found to be 1 : 1. In addition, ¹H NMR titration and DFT theoretical studies supported the results. Real sample analysis of cyanide in domestic water samples and cow urine samples were obtained quantitatively.