Thiophene aldehyde-diamino uracil Schiff base: A novel fluorescent probe for detection and quantification of cupric, silver and ferric ions

摘要

A new Schiff base from the condensation of 5,6-diamino-1,3-dimethyluracil with 5-methylthiophe ne-2-carboxaldehyde was synthesized. The compound was characterized by spectral data (UV-Vis, IR, H-1 NMR, fluorescence, MS). Ethanolic solutions of the Schiff base exhibit a strong fluorescence emission at 385 nm (lambda(ex) = 341 nm), and have been employed as a "turn-off' fluorescent probe for selective detection of Ag+, Cu2+ and Fe3+ ions in presence of other cations such as Na+, K+, Ca2+ and Mg2+ ions abundant in natural water. The interaction between the tested compound and copper, silver or iron ions is associated with a significant fluorescence decrease, showing detection limits of 2.1-14.2 ppb. Under optimal conditions, the developed sensor was successfully employed to determine Ag+, Cu2+ and Fe3+ ions in real samples and proved to be selective and sensitive. (c) 2015 Elsevier B.V. All rights reserved.