Source: Current Analytical Chemistry, Volume 11, Number 4, October 2015, pp. 279-290(12)
Publisher: Bentham Science Publishers
Hassan H. Hammud*1, Mohammad H. El-Dakdouki2, Nada Sonji2, Ghassan Sonji2 and Kamal H. Bouhadir3
1Department of Chemistry, Faculty of Science, King Faisal University, Al-Ahsa 31982, Saudi Arabia;
2Department of Chemistry, Faculty of Science, Beirut Arab University, Debbieh, Lebanon;
3Department of Chemistry, Faculty of Arts and Sciences, American University of Beirut, Beirut,Lebanon
Water quality surveillance is given maximum priority, for safety assessment of the environment and human health in particular. Among the inorganic contaminants of water, heavy metals are getting much attention because of their non-biodegradable nature and permanent accumulation in living tissues causing lethal biological disorders. Consequently, there is a growing urgency for the development of simple, quick, versatile, and reliable methods for control recognition of metal ions at very low concentrations. In this context, N-[[(6-Amino-1,2,3,4-tetrahydro-1,3-dimethyl-2,4-dioxo-5-pyrimidinyl)amino]thioxomethyl]- benzamide, a novel diaminouracilbenzoylthiourea (DAUTU)-based fluorescent probe was synthesized in high yield via a single-step facile reaction, and characterized by various spectral techniques. The chemically stable probe exhibited strong fluorescent emission at 385 nm upon excitation at 362 nm. The probe has been successfully deployed for the selective detection and accurate determination of trace amountsof Ag+, Cu2+ and Fe3+ ions in aqueous samples spiked with competing metal ions, as well as in natural water samples thus demonstrating its versatile applicability. The detection was pH-independent, and detection limits ranged from 0.0716-0.286 μM for the analyzed cations which is sufficiently well below the safety levels set by U.S. EPA. Importantly, detection was achieved in short response times with high accuracy, reproducibility, sensitivity, and reversibility.
The sensing principle is based on remarkable fluorescence quenching in presence of the detected metal ions via excitation energy transfer from the probe to the d-orbital in the atoms of the metals. In summary, we developed an efficient, cost effective, and easily operated uracil-based chemosensor for the rapid detection and sensitive determination of Ag+, Cu2+ and Fe3+ ion concentrations in diverse real world applications.