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

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Molecular and biomolecular spectroscopy, 2015-11, Vol.150, p.94-103
• Main Authors: Hammud, Hassan H., El Shazly, Shawky, Sonji, Ghassan, Sonji, Nada, Bouhadir, Kamal H.
• Format: Article
• Language: English
• Subjects: 5,6-Diamino-1,3-dimethyluracil; Ag+/Cu2+/Fe3+ ions; Fluorescence probe; Methyl-2-thiophenecarboxaldehyde; Schiff base; Water pollution
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2015.05.038

[Display omitted] •A novel Schiff base fluorescent chemosensor was easily prepared by a one-step reaction.•The probe shows significant fluorescence quenching in presence of Ag+, Cu2+ and Fe3+ ions.•Limits of detection can reach 0.132μM (Ag+), 0.088μM (Cu2+) and 0.037μM (Fe3+).•The analytical method was validated for the assay of the three cations in real samples. A new Schiff base from the condensation of 5,6-diamino-1,3-dimethyluracil with 5-methylthiophene-2-carboxaldehyde was synthesized. The compound was characterized by spectral data (UV–Vis, IR, 1H NMR, fluorescence, MS). Ethanolic solutions of the Schiff base exhibit a strong fluorescence emission at 385nm (λex=341nm), 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 2.1–14.2ppb. 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.