Stable lanthanide metal–organic frameworks as ratiometric fluorescent probes for the efficient detection of riboflavin

Abstract

The rational design and exploration of fluorescent probes for the efficient detection of riboflavin (RF) is of great significance. Herein, a series of isostructural Ln-MOFs (Ln-BPTA) with different metal nodes (Eu, Sm, Dy and Tb) and the same nitrogen-abundant ligand have been successfully prepared via simple hydrothermal self-assembly. The as-prepared Ln-BPTA systems exhibit excellent structural stability and nanoscale morphology, and can directly serve as fluorescent probes towards the ratiometric fluorescence detection of RF. In particular, Eu-BPTA delivers the best response performance among the designed isostructural homologues, showing a rapid response (within seconds), an ultralow limit of detection (5.02 nM), excellent durability and high selectivity, even in the actual matrix. Furthermore, the Förster resonance energy transfer (FRET) mechanism between Ln-BPTA and RF is responsible for the fluorescence detection process, and the enhanced performance of Eu-BPTA can be attributed to its modulated luminescence properties, achieving the optimal FRET efficiency for RF detection. The present study sheds light on the rational design and synthesis of new Ln-MOF-based probes for RF detection, and stimulates the extensive exploration of Ln-MOFs with tunable luminescence properties for potential fluorescence detection applications.