Rhodamine-6G hydrazide probe for selective determination of Cu(II) in aqueous media

A new fluorescence method for selective determination of Cu 2+ using rhodamine 6G hydrazide (R6GH) as a probe has been developed. The probe has shown selective and sensitive fluorescence response toward Cu 2+ in aqueous media. In the proposed reaction mechanism the hydrazide group of R6GH binds to Cu 2+ exhibiting a behavior similar to α-amino esters, which results in a redox hydrolysis of the hydrazide moiety with the release of highly fluorescent rhodamine 6G. Under the optimal conditions the fluorescence enhancement at 545 nm was linearly related to the concentration of Cu 2+ in the range 0.1-10 μmol L -1 . The proposed method has been applied to the determination of trace Cu 2+ in water samples with satisfactory results.