Fluorescence water sensor based on covalent immobilization of chalcone derivative

A new fluorescence sensor for determining water content in organic solvents has been successfully demonstrated based on a fluorescent dye. 4'-N,N-dimethylamino-4 methylacryloylamino chalcone (DMC), in which the charge donor and acceptor parts were both contained, was copolymerized with acrylamide, hydroxyethyl methacrylate and triethylene glycol dimethacrylate onto glass surface. The fluorescence intensity of DMC decreased with increasing of water content in organic solvents owing to the formation of solvate complexes. DMC fluorescence intensity changed as a linear function of water content in the range of 0-6% in the samples of acetone, ethanol, and acetonitrile solutions. Satisfactory reproducibility, reversibility and a short response time were realized. With the optimum membrane described, detection limits were of 0.006%, 0.008%, and 0.002% for acetone, ethanol, and acetonitrile, respectively. The sensing membrane was found to have a lifetime at least 2 months.