Single-Probe Triple-Emission Eu/Tb-MOF Sensor Array for Multidimensional Discrimination of Amino Acids

Using a mixed-lanthanide strategy, a bimetallic Eu/Tb-MOF with triple emission centers was synthesized. Under single-wavelength excitation, it simultaneously exhibits ligand-centered emission at 400 nm and the characteristic emissions of Eu³⁺ and Tb³⁺ at 615 and 545 nm, respectively, generating a distinctive triple-color fluorescence fingerprint. Then, a single-probe fluorescence sensor array was constructed, realizing the discrimination of 10 structurally similar amino acids with 100% classification accuracy. The array also showed reliable analytical performance in real samples, including honey and juice. FTIR, UV-vis, and fluorescence lifetime analyses supported ground-state interactions between amino acids and Eu/Tb-MOF, with amino-, hydroxyl-, and carboxylate-related groups likely playing key roles. Furthermore, the material was processed into fluorescent encryption inks and UV-curable composite coatings for information concealment and advanced anticounterfeiting applications. This work provides a simple and efficient strategy for multidimensional amino acid discrimination and highlights the potential of multifunctional Ln-MOFs in integrated sensing and security technologies.