Carbon nanotube-based nanocomposite sensor tuned with a catechol as novel electrochemical recognition platform of uranyl ion in aqueous samples

This article reports a novel electrochemical recognition platform based on a nanocomposite carbon paste electrode containing carbon nanotubes modified with gold nanoparticles carrying a thiolated catechol for the fast amperometric determination of uranyl ion (UO22+) in water. Recognition of UO22+ is accomplished by supramolecular chemistry due to the formation of an inclusion complex between catechol and UO22+. The amperometric device operates at –0.40 V vs. Ag/AgCl, where the reduction of UO22+ takes place on the electrode surface, covering a linear range from 0.49 to 170 μg L−1 UO22+ in a 0.1 M boric acid buffer solution at pH 5.3. The developed sensing system presents good response towards UO22+ in aqueous environmental samples, with good selectivity over other browsed cations and can be easily reset by simple polishing. This platform has demonstrated to be a potential alternative regarding to the common standard bench-top analytical techniques for the development of in-field devices for in-situ monitoring.This work was supported by the Spanish project CTQ2012-36165 and CTQ2013-41161-R. Authors also want to thank the support of the Generalitat de Catalunya to GSB (2014-SGR-837), MERS (2014-SGR-1356) and GTS (2014-SGR-1152). Real samples from mine wells rich in uranyl ion were kindly supplied by Berkeley Energia and Consejo de Seguridad Nuclear (National Security Council, CSN-2015). Dr. J. Muñoz gratefully acknowledges the “Juan de la Cierva” programme.Peer reviewe