In this work, a new MOF Eu-BTC-BDC-NH₂ (BTC = benzene-1,3,5-tricarboxylate, BDC-NH₂ = 2-aminoterephthalic acid) was synthesized by a facile and energy-efficient process, and can be utilized as a highly sensitive and selective ratiometric fluorescence probe for phosphate (Pi). The produced Eu-MOF had two emission peaks at 425 nm and 617 nm, which came from the BDC-NH₂ ligand and energy transfer effect between the two ligands and Eu³⁺, respectively. When contact with Pi, due to the ultra-high affinity between Eu³⁺ and the oxygen atoms in Pi, part of the ligands were replaced and P-O-Eu bonds formed. Accordingly, the energy transfer effect was weakened, and the fluorescence intensity at 617 nm reduced, however, the peak at 425 nm increased. Based on this, a Pi ratiometric fluorescence platform with excellent performance was established with a low detection limit (LOD) of 0.07 μM and superior selectivity for 19 common ions and 6 phosphate-containing molecules. In addition, the sensor achieved satisfactory results in the detection of environmental water samples. Finally, a portable detection kit based on hydrogel-MOFs was successfully constructed by combining with a smartphone, which can realize on-site monitoring of Pi.

在这项工作中，通过一种简便、节能的工艺合成了一种新的 MOF Eu-BTC-BDC-NH ₂ (BTC = 苯-1,3,5-三羧酸盐，BDC-NH ₂ = 2-氨基对苯二甲酸)，并且可用作磷酸盐 (Pi) 的高灵敏度和选择性比率荧光探针。制备的Eu-MOF在425 nm和617 nm处有两个发射峰，分别来自BDC-NH ₂配体和两个配体与Eu ³⁺之间的能量转移效应。^{当与 Pi 接触时，由于 Eu 3+}之间的超高亲和力Pi中的氧原子，部分配体被取代，形成PO-Eu键。相应地，能量转移效应减弱，617 nm处的荧光强度降低，而425 nm处的峰增加。在此基础上，建立了性能优异的Pi比率荧光平台，检测限(LOD)低至0.07 μM，对19种常见离子和6种含磷酸盐分子具有优异的选择性。此外，该传感器在环境水样的检测中取得了令人满意的效果。最后，结合智能手机成功构建了基于水凝胶-MOFs的便携式检测试剂盒，可实现对Pi的现场监测。