科研之友
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摘要
A highly selective colorimetric and fluorescent sensor for Hg2+, TPS (TPS = 2-(4-(diphenyl-amino)phenyl)quinazoline-4(3H)-thione), based on a 2-substituted quinazoline-4(3H)-thione derivative, was designed and characterized in this paper. TPS displays relatively strong fluorescence centered at about 468 nm. When mixing with Hg2+, TPS interacts with Hg2+ in a 2 : 1(TPS-Hg2+) stoichiometry via a coordination bond interaction between the sulfur atom and Hg2+ with an association constant of 4.17 x 10(8) M-2 (R-2 = 0.96). Upon addition of Hg2+, TPS showed a remarkable decrease in fluorescence spectra (468 nm) with a clear color change from yellow to red, so TPS could serve as a naked-eye sensor for Hg2+. The sensor allow determination of Hg2+ in the working range 2.0 mM-12.0 mu M with a detection limit of 1.5 mu M. Upon addition of KI to the solution of TPS-Hg2+ species, the spectra can be restored to the original spectrum in both absorption and fluorescence and indicates that this sensor could be reused. The sensor exhibited excellent reproducibility, reversibility and selectivity.
