ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Dye-encapsulated metal–organic framework composites for highly sensitive and selective sensing of oxytetracycline based on ratiometric fluorescence

Peng-Chen Su, Long Yu, Mi Yuan, Ling-Xiao Wang, Ming-Tai Sun, Wei-Jie Hu, Hua Tan, and Su-Hua Wang

MOE Key Laboratory of Resources and Environmental System Optimization, College of Environmental Science and Engineering, North China Electric Power University, Beijing, People’s Republic of China

E-mail: wangsuhua@ncepu.edu.cn

Received: 3 October 2022  Accepted: 10 December 2022

Abstract:

Herein, we reported a class of well-fluorescence-stabilized rare-earth-free ratiometric fluorescent probe for highly sensitive visual detection of oxytetracycline (OTC), which was fabricated by encapsulation of blue-emitting dye 2-aminoterephthalic acid into nanopores of aluminum-based metal–organic framework MIL-53(Al) with microflower morphology (denoted as FMIL-53(Al)). The surface-distributed abundant open aluminum sites of FMIL-53(Al) can coordinate and fix the conformation of OTC molecules, which selectively increases the fluorescent quantum yield of OTC at ~ 520 nm. The dye in the probe is inert to the analyte, and the blue fluorescence intensity is constant. When the green fluorescence of OTC increases, a continuous color evolution from blue to green is observed. For sensing applications, NH₂-BDC@FMIL-53(Al)-3 was selected as the sensor. The optimized conditions for the sensing process were as follows: sensing medium was HEPES buffer (10 mM, pH = 7.3), probe concentration: 0.1 mg/mL; incubation time: 45 min; optimal excitation wavelength: 383 nm. The detection limit was estimated to be 11.0 nM, which is considered to be one of the most sensitive ratiometric fluorescent probes for OTC detection. More importantly, a smartphone-based sensing method was developed, providing a promising non-instrument-based technique for the reliable, semi-quantitative assay of OTC in the field.

Graphical abstract

Keywords: Ratiometric fluorescence; Oxytetracycline (OTC); Visual monitoring; Smartphone platform

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-022-02629-8

Chemical Papers 77 (4) 2295–2308 (2023)