Production of reusable and colorimetric cyanide sensor hydrogels for rapid detection of cyanide ions in various aqueous media

Abstract

In this study, a new type of (hemi)cyanine dye-derived HC-M monomer suitable for hydrogel synthesis by redox polymerization method was developed and characterized by various methods. The feature of HC-M monomer is that it changes color in the presence of CN⁻ ions. Thus, when added to any hydrogel structure as a comonomer with covalent bonds, hydrogels that are highly sensitive to CN⁻ ions and function colorimetrically can be produced. For this purpose, p(AAm-co-HCM) hydrogels were synthesized. The synthesized hydrogels were characterized by swelling tests, Fourier transform infrared spectroscopy (FTIR), and Scanning Electron Microscopy (SEM) analyses. The synthesized and characterized new type of monomer and p(AAm-co-HCM) hydrogels were used to detect CN⁻ ions in various aqueous media and some liquid foods. For this, various concentrations of CN⁻ in the range of 0.05–100 ppm were used. Thus, a new type of hydrogel structure was produced that qualitatively determines the presence of CN⁻ in any aqueous environment by changing color in the time range of 1–660 min. It has been shown that the resulting hydrogels can be used as sensors many times, suitable for regeneration, thanks to their covalent bonds.