Fluorescent Recognition of Adenosine Triphosphate and Uric Acid by two Eu-Based Metal-Organic Frameworks

Two Eu-based MOF fluorescent sensors, Eu2(CHDA)2(C2O4)(H2O)4 (1) (CHDA = 1,4-cyclohexanedicarboxylic acid, C2O4 = oxalate group) and Eu2(PDA)3(H2O)3 (2) (p-phenylenediacetic acid = PDA), were prepared for the rapid detection of uric acid (UA) and adenosine triphosphate (ATP). The properties of the sensors were elucidated using photoluminescence spectrosopy and UV-vis absorption spectroscopy. The results reveal that compound 1 suspension can selectively recognize ATP by fluorescence quenching, and compound 2 suspension exhibits a special selectivity for UA, all of which are due to the spectral overlap and energy competition and transfer. The two MOF-based sensors feature high quenching efficiencies Ksv (5.49 × 104 M−1 for ATP; 1.14 × 104 M−1 for UA), low detection limits (ATP: 0.490 μM; UA: 0.601 μM) and fast response times (in seconds). Accordingly, the excellent selectivity and sensitivity for ATP and UA can be realized by a “turn-off” fluorescence response. In addition, the two fluorescent MOFs can also enable the fabrication of test strips, which provided a low cost, simple and flexible way to detect trace amounts of UA and ATP in aqueous solutions or organisms. This work provides new perspectives for the development of rare-earth MOFs in detecting uric acid and adenosine triphosphate, possessing the potential for possible applications in real-life scenarios.