A highly sensitive and reversible chemosensor for Hg(2+) detection based on porphyrin-thymine conjugates

In this study, we demonstrated a highly sensitive, selective, and reversible chemosensor for Hg(2+) determination. This chemosensor was synthesized by direct condensation of thymin-1-ylacetic acid with zinc tetraaminoporphyrin, which has a porphyrin core as the fluorophore and four thymine (T) moieties as the specific interaction sites for Hg(2+) . The probe (4T-ZnP) exhibited split Soret bands with a small peak at 408 nm and a strong band at 429 nm in a dimethylformamide/H2 O (7/3, v/v) mixed solvent as well as a strong emission band at 614 nm. Upon the addition of Hg(2+) , the probe displayed strong fluorescence quenching due to the formation of T-Hg(2+) -T complexes. With the aid of the fluorescence spectrometer, the chemosensor in the dimethylformamide/H2 O (7/3, v/v) mixed solvent (0.3 μM) exhibited a detection limit of 6.7 nM. Interferences from other common cations, such as Co(2+) , K(+) , Sn(2+) , Zn(2+) , Cu(2+) , Ni(2+) , Mn(2+) , Na(+) , Ca(2+) , Mg(2+) , Pb(2+) , and Cd(2+) , associated with Hg(2+) analysis were effectively inhibited.