A Terbium Ion-Based Dual-Ligand Fluorescent Probe for Highly Selective and Sensitive Detection of Cu Ions.

In this study, a fluorescent probe (GMP-Tb-SSA) utilizing lanthanide coordination polymer nanoparticles, GMP-Tb, as a sensing platform, and 5-sulfosalicylic acid (SSA) as a cofactor ligand was proposed for the detection of copper ions (Cu). GMP-Tb was synthesized by the self-assembly of guanine monophosphate (GMP) and terbium ion (Tb), and SSA was introduced as a sensitizer into the GMP-Tb network. Cu could efficiently inhibit the electron transfer from the ligand GMP to the central ion, Tb, leading to a significant quench of fluorescence of Tb. The method is highly selective with a linear range of 0 to 21 µM and a detection limit of 300 nM. It is not interfered by metal ions, amino acids, and other species, and can be successfully applied to the detection of Cu in real water samples.