A highly selective optical sensor for the detection of cyanide ions in aqueous solution and living cells

A fluorogenic naphthalene based receptor (NFS) has been successfully generated by preparation from 3-amino-2-naphthol and 2-hydroxy-1-naphthaldehyde, it was then characterized. Optical and colorimetric properties of the receptor (NFS) in terms of cyanide (CN-) ions were investigated by several methods including naked-eye detection, UV–vis spectrophotometry and fluorescence spectroscopy. A visual color change from yellow to orangish-pink was observed upon interaction of the receptor with cyanide (CN-) ions in solution, while no color change appeared upon addition of the other anions tested. The detection limit of NFS was calculated as 0.21 µM without any interaction with other anions tested which is lower than that described by the World Health Organization for CN– ions in drinking water. It can be concluded that the receptor (NFS) was sensitive and rapid enough for the detection of CN- ions in solutions. The interaction between the receptor and CN– ions was also investigated by 1H NMR titration, MALDI-Tof mass spectrometry, and FTIR-AR spectroscopy. NFS was also applied to the bio-imaging of human epithelial cell line (HEK 293) and the cell imaging studies demonstrated that the receptor was capable of detecting cyanide ions in living cells.