Design and Synthesis of a Terbium(III) Complex-Based Luminescence Probe for Time-Gated Luminescence Detection of Mercury(II) Ions

摘要

Time-gated luminescence detection technique using lanthanide complexes as luminescent probes is a useful and highly sensitive method. However, the effective application of this technique is limited by the lack of the target-responsive luminescent lanthanide complexes that can specifically recognize various analytes in aqueous solutions. In this work, a dual-functional ligand that can form a stable complex with Tb3+ and specifically recognize Hg2+ ions in aqueous solutions, N,N,N 1 ,N 1 -{[2,6-bis(3′-aminomethyl-1′-pyrazolyl)-4-[N,N-bis(3″,6″-dithiaoctyl)-aminomethyl]- pyridine]} tetrakis(acetic acid) (BBAPTA), has been designed and synthesized. The luminescence of its Tb3+ complex is weak, but can be effectively enhanced upon reaction with Hg2+ ions in aqueous solutions. The luminescence response investigations of BBAPTA-Tb3+ to various metal ions indicate that the complex has a good luminescence sensing selectivity for Hg2+ ions, but not for other metal ions. Thus a highly sensitive time-gated luminescence detection method for Hg2+ ions was developed by using BBAPTA-Tb3+ as a luminescent probe. The dose-dependent luminescence enhancement of the probe shows a good linearity with a detection limit of 17 nM for Hg2+ ions. These results demonstrated the efficacy and advantages of the new Tb3+ complex-based luminescence probe for the sensitive and selective detection of Hg2+ ions.