A Highly Stable Lanthanide-Organic Framework for Ultrasensitive Dynamic Luminescence Detection of Quercetin

Quercetin is widely regarded as a promising therapeutic agent with multifaceted protective effects on the cardiovascular system, but its luminescence-based detection in actual samples remains challenging due to weak host-guest interactions. In this work, a highly stable mixed ligand lanthanide-organic framework ({[Eu₂(BETC)(NDC)(H₂O)(DMF)]·2.5H₂O}_n, HBNU-21-Eu) was prepared through a solvothermal reaction using 1,2,4,5-benzenetetracarboxylic acid (H₄BETC) and 1,4-naphthalenedicarboxylic acid (H₂NDC) as mixed ligands and Eu³⁺ ion as a node. HBNU-21-Eu displays good pH/solvent/thermo stability and intense red luminescence with a high quantum yield of 70.2%. Rapid luminescence detection of quercetin was successfully achieved within 30 s through a highly efficient dynamic quenching process, with a high quenching constant of 5.08 × 10⁴ M^-1 and a low detection limit of 0.57 μM. The actual sample detection capabilities of quercetin in tap water samples and jasmine tea were verified with satisfactory recovery rates.