A multi-analyte selective dansyl derivative for the fluorescence detection of Cu(ii) and cysteine

Abstract

A new multi-analyte selective fluorescence chemosensor DA was synthesized by a simple one pot reaction between dansyl chloride and 2-aminobenzohydrazide in the presence of a base. In DMSO : H₂O (1 : 1, v/v), the fluorescence of DA at 483 nm was blue shifted and enhanced at 474 nm along with a new shoulder peak appearing at 411 nm selectively in the presence of Cu²⁺ among the other tested metal ions due to the chelation enhanced fluorescence (CHEF) effect. Without any noticeable interference from potentially competitive metal ions, sensor DA can detect Cu²⁺ down to 9.79 × 10⁻⁷ M. Sensor DA gives satisfactory results for the quantification of Cu²⁺ in real water samples. Sequentially, the resultant in situ generated DA–Cu²⁺ complex is applied for the selective sensing of bioactive cysteine with a detection limit down to 1.76 × 10⁻⁶ M.