Selective colorimetric and "turn-on'' fluorimetric detection of cyanide using an acylhydrazone sensor in aqueous media

A simple, selective colorimetric and fluorimetric cyanide chemosensor L was designed and synthesized, which showed both colorimetric and fluorescence turn-on responses for cyanide ions in aqueous solution with specific selectivity and high sensitivity. The probe shows an immediate visible change in color from colorless to yellow only after the addition of CN- in aqueous solution; these color changes can be readily observed visually. Moreover, the detection limit on fluorescence response of the sensor to CN is down to 1.20 x 10(-9) M, which is far lower than the maximum level of 1.9 x 10(-6) M for cyanide in drinking water according to WHO guidelines. Test strips based on L were fabricated, which could be used as a convenient and efficient CN-test kit to detect CN- in aqueous solution for "in-thefield'' measurement.