Development of AIEE active fluorescent and colorimetric probe for the solid, solution, and vapor phase detection of cyanide: smartphone and food applications

Abstract

Apart from environmental implications, the extreme toxicity of cyanide can lead to sudden human death upon prolonged exposure to it. Hence, rapid and low-level on-site detection of cyanide has earned paramount significance in the present era. Therefore, an AIEE active and piezofluorochromic Schiff base (probe 2) was synthesized which exhibited highly selective fluorescence enhancement based nanoscale (LOD; 6.17 nM) detection of CN⁻. The interaction mode was attributed to the deprotonation of the probe by the cyanide that was confirmed through ¹H NMR titration, pH, theoretical studies, and switchable fluorescence response upon the addition of HCl. Advantageously, probe 2 displayed solid and vapor phase recognition of cyanide which is the first of its kind as far as we know. The excellent sensing potential of the probe was satisfactorily applied for the detection of cyanide in food, natural soil, and industrial wastewater. Additionally, probe 2 showed an immediate colorimetric response towards cyanide which was favorably integrated through a smartphone. Finally, the switchable fluorescence response of the probe was used to design an INHIBIT logic gate. Therefore, the multifunctional probe 2 displayed excellent practical potential for cyanide detection which was the ultimate goal of our work.