Preparation of dual-ligands Eu-MOF nanorods with dual fluorescence emissions for highly sensitive and selective ratiometric/visual fluorescence sensing phosphate

• Published in: Sensors and actuators. B, Chemical Chemical, 2022-09, Vol.367, p.132008, Article 132008
• Main Authors: Shi, Wei, Zhang, Shangqing, Wang, Yu, Xue, Y.D., Chen, Mingli
• Format: Article
• Language: English
• Subjects: Atomic properties; Benzene; Bonding strength; Dual emissions; Energy transfer; Eu-BTC-BDC-NH2; Europium; Facile synthesis; Fluorescent indicators; Hydrogels; Ligands; Metal-organic frameworks; Nanorods; Oxygen atoms; Phosphate detection; Selectivity; Water sampling
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2022.132008

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. [Display omitted] •A new MOF Eu-BTC-BDC-NH2 was synthesized by a facile and energy-efficient process.•The generated Eu-MOF can be used as a ratiometric fluorescence probe for phosphate.•The established sensor had high sensitivity and excellent selectivity.•A detection kit based on hydrogel-MOFs was built to realize on-site monitoring of Pi.