Decoding and quantitative detection of antibiotics by a luminescent mixed-lanthanide-organic framework

Due to the potential risk of antibiotics to the environment, the development of inexpensive, simple, and reliable antibiotic detection methods is significant but also faces challenges. In this work, several lanthanide-organic frameworks (LOFs), constructed from lanthanide ions (Eu3+ and/or Tb3+) and 1,3,5-benzene-tricarboxylic acid (BTC), were synthesized by solvothermal method. LOF-S3 with comparable emission peaks of D-5(4) -> F-7(5) (Tb3+, 545 nm) and D-5(0) -> F-7(2) (Eu3+, 618 nm) was selected as a luminescent sensor. In this system, the highly efficient energy transferred from the organic linker to lanthanide ions and from Tb3+ to Eu3+ occurs. LOF-S3 sensor was capable of decoding antibiotics by distinguishable emission intensity ratios. Therefore, a two-dimensional decoded map of antibiotics was established. The linear relationship between antibiotic concentration and emission intensity ratio indicated the quantitative determination of antibiotics was feasible. As a typical analyte, the response mechanism of nalidixic acid (NA) was investigated in detail. The competition of NA and BTC for UV light absorption, as well as the binding propensity of NA and Tb, affected the organic linkers-to-lanthanide ions and Tb-to-Eu energy transfer, resulting in the change of fluorescence intensity ratio. The self-calibrating mixed-LOF sensor overcame the uncontrollable errors of the traditional absolute emission intensity method and generated stable luminescent signals in multiple cycles. Furthermore, the integration of LOF-S3 with polymer fibers enabled the formation of a LOF-polymer fibrous composite with fluorescence detection capability, which is a promising portable sensor for practical applications. (C) Higher Education Press 2022

Automated summary

Due to the potential risk of antibiotics to the environment, the development of inexpensive, simple, and reliable antibiotic detection methods is significant but also faces challenges. In this study, lanthanide-organic frameworks (LOFs) were synthesized and used as luminescent sensors for decoding and quantifying antibiotics. Furthermore, a LOF-polymer fibrous composite with fluorescence detection capability was formed, showing promise for practical applications.