A highly sensitive and reversible chemosensor for Hg2+ detection based on porphyrin-thymine conjugates

In this study, we demonstrated a highly sensitive, selective, and reversible chemosensor for Hg2+ 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 Hg2+. The probe (4T-ZnP) exhibited split Soret bands with a small peak at 408nm and a strong band at 429nm in a dimethylformamide/H2O (7/3, v/v) mixed solvent as well as a strong emission band at 614 nm. Upon the addition of Hg2+, the probe displayed strong fluorescence quenching due to the formation of T-Hg2+-T complexes. With the aid of the fluorescence spectrometer, the chemosensor in the dimethylformamide/H2O (7/3, v/v) mixed solvent (0.3 mu M) exhibited a detection limit of 6.7 nM. Interferences from other common cations, such as Co2+, K+, Sn2+, Zn2+, Cu2+, Ni2+, Mn2+, Na+, Ca2+, Mg2+, Pb2+, and Cd2+, associated with Hg2+ analysis were effectively inhibited. Copyright (C) 2015 John Wiley & Sons, Ltd.