Preparation and L-Tryptophan sensing performance of Tb³⁺ decorated fluorescent MOF

• Main Authors: GAO Xin-li, PEI Lei, ZHAO Xu-dong, GAO Zhu-qing, HUANG Hong-liang
• Format: Article
• Language: zho
• Published: Journal of Materials Engineering 2021-06-01
• Series: Journal of Materials Engineering
• Subjects: metal-organic framework; post-synthesis modification; tryptophan; fluorescence quenching
• Online Access: http://jme.biam.ac.cn/CN/10.11868/j.issn.1001-4381.2021.000076

For selectively sensing Tryptophan(Trp), the fluorescent Tb³⁺@UiO-66-(COOH)₂ was prepared through loading Tb³⁺ into UiO-66-(COOH)₂ <i>via</i> post-synthesis method. Transmission electron microscope (TEM), X-ray powder diffractometer (XRD), specific surface area analyzer, and X-ray photoelectron spectroscope (XPS) were used to analysize the morphology, composition and pore characteristics of the porous materials. Meanwhile, ultraviolet-visible spectrophotometer (UV-Vis) and fluorescence spectrophotometer were used to study the fluorescence characteristics. The results show that the energy transfer from organic ligand to Tb³⁺ leads to a bright green fluorescence. Among the 13 amino acids, only Tryptophan has obvious fluorescence quenching effect. This is because there appears a large overlap between UV-Vis absorption spectrum of Trp and excitation spectrum of the MOF, which indicates a strong competition effect for UV light. The absorption to UV light of Tb³⁺@UiO-66-(COOH)₂ is decreased by Trp,leading to the weak fluorescence. Further investigation indicates the material can sensitively sense Trp (LOD, 5.53 <i>μ</i>mol/L) and owns excellent anti-interference ability from other co-existing amino acids. Thus, this work not only demonstrates Tb³⁺@UiO-66-(COOH)₂ can serve as a selective and sensitive sensor for Trp, but also provides a guideline for designing novel sensors for amino acids in the future.