Ratiometric Detection of Cu2+ Using a Luminol-Tb-GMP Nanoprobe with High Sensitivity and Selectivity

A novel ratiometric fluorescent method for the detection of copper ions (Cu2+) based on the stimulus-responsive dual-ligand lanthanide luminol-Tb-GMP coordination polymer nanoparticle (CPNP) fluorescent probe is reported in this study. The luminol-Tb-GMP CPNPs are composed of Tb3+ as the center metal ions and ligand of GMP together with the cofactor luminol ligands as the bridging ligands. In the presence of Cu2+, the fluorescence of GMP-Tb as the response moiety is dynamically quenched, while the fluorescence of luminol used as the reference remains constant. Hence, ratiometric fluorescent monitoring of Cu2+ can be achieved by measuring the ratio of the fluorescence at the 430 nm (F430) wavelength of luminol to the 547 nm (F547) wavelength of Tb3+ in the fluorescent spectra of the luminol-Tb-GMP CPNPs suspension. In this sensing approach, when Cu2+ coordinates with a luminol/GMP unit, the fluorescence of the Tb3+ units located in the vicinity Cu2+ will also be quenched. Thus, the sensing sensitivity is h...