Dual luminescent lanthanide coordination polymers for ratiometric sensing and efficient removal of Hg 2

In this work, we report a new fluorescence ratiometric method for Hg 2+ assay based on the dual-ligand fluorescent probe GMP–Tb–luminol coordination polymers (CPs), which can be excited at the same wavelength and reveal characteristic luminescence of Tb 3+ and luminol with spectrally distinguishable emission peaks. The addition of Hg 2+ leads to the decrease of Tb 3+ luminescence due to the higher coordination between Hg 2+ and GMP, which inhibits energy transfer from GMP to Tb 3+ . Meanwhile, the fluorescence of luminol increases because of the aggregation-induced emission phenomenon. Therefore, a ratiometric fluorescent sensor for Hg 2+ assay can be constructed by measuring the ratio of fluorescence intensity of luminol at 430 nm ( I 430 ) to that of Tb 3+ at 548 nm ( I 548 ). Under the optimal conditions, the fluorescence intensity ratio I 430 / I 548 exhibits a good linear relationship versus the concentration of Hg 2+ in the range from 5 nM to 130 μM with a low detection limit of 1.3 nM. Additionally, the probe can also adsorb Hg 2+ in water with high efficiency, which makes Hg 2+ removal in water possible. The proposed method has been successfully used for the determination of Hg 2+ in tap water, indicating its potential applications in the detection of Hg 2+ pollution in environmental water.