A Simple Hydrazide Derivative as a Selective Chemosensor for Cyanide Ion Detection in Tobacco and Other Food Samples
A hydrazide derivative SR‐03 , was synthesized from 2‐(phenylamino) benzoic acid and 4‐hydrazinylbenzonitrile hydrochloride for the selective detection of cyanide (CN – ) ions. The sensing behavior of SR‐03 was investigated by UV–vis absorption spectroscopy in acetonitrile, where it exhibited a distinct color change from cream to yellow upon interaction with CN − ion. The probe displayed sensitivity toward cyanide with a detection limit of 5.37×10 −7 M and a binding constant of 1.41×10 6 M −1 . The sensing mechanism involves CN − induced deprotonation followed by intra‐ligand charge transfer, which was supported by 1 H NMR titration, electrochemical studies, and DFT calculations. Binding studies revealed a 1:2 stoichiometric interaction between SR‐03 and CN − . The sensing process was reversible upon the addition of trifluoroacetic acid, demonstrating the reversible sensing behavior of the probe. Furthermore, SR‐03 was successfully employed for cyanide detection in dietary and real samples, including sprout potatoes, bamboo shoots, tobacco, palak, flax seeds, and cluster bean seeds. The practical applicability of the probe was further demonstrated through a simple probe colorimetric test kit using filter paper strips.