A highly selective colorimetric and “Off-On” fluorescence sensor for CN− based on Zn(salphenazine) complex

The development of sensors for selective detection of cyanide ion (CN−) is an important mission to accomplish because of the versatility and toxicity of CN−. In the present work, an “ensemble”-based colorimetric and fluorescent sensor (L2-Zn2+) for CN− ion has been developed. The addition of cyanide ions removed Zn2+ from the ensemble (L2-Zn2+) in aqueous medium, resulting in a color change of the solution from red to buff and a “turn-on” fluorescent response. Also, the sensitivity of both the fluorescence- and colorimetric-based assay is below the maximum allowable level of cyanide ions in drinking water set by the World Health Organization. In addition, test strips, which served as convenient and efficient CN− test kits, were fabricated based on the sensor. Notably, the selective detection of cyanide with L2-Zn2+ for practical application was also performed in sprouting potatoes.