A Tb3+ functionalized triazine-porous organic framework as a ratiometric fluorescent sensor for determination of ciprofloxacin in aquatic products

Abstract

A Tb³⁺ functionalized triazine-porous organic framework (Tb³⁺/TAPOF) was prepared by introducing Tb³⁺ into a triazine-porous organic framework through a coordination bond. Combining the advantages of both Tb³⁺ and TAPOF, Tb³⁺/TAPOF showed good thermal stability, a high specific surface area, and excellent fluorescence performance. As the concentration of ciprofloxacin became higher, the intensity of the peak at 544 nm increased, while that of the peak at 440 nm did not change. Thus, a ratiometric fluorescent sensor based on Tb³⁺/TAPOF for selective ciprofloxacin determination was constructed, and the mechanism of ciprofloxacin determination was studied using the UV-vis and phosphorescence spectra and fluorescence lifetime. A good linear relationship, under the optimized conditions, was obtained between the I₅₄₄/I₄₄₀ value and the ciprofloxacin concentration in the range of 0.06 μmol L⁻¹ to 5.0 μmol L⁻¹, and the limit of detection (LOD, S/N = 3) was 19 nmol L⁻¹. Moreover, the ratiometric fluorescent sensor based on Tb³⁺/TAPOF was applied to the determination of ciprofloxacin in aquatic products with recoveries in the range of 96.1–108.6%. These results obtained by the ratiometric fluorescence method and the high-performance liquid chromatography (HPLC) method are consistent for determination of aquatic products, which further proves that this method based on Tb³⁺/TAPOF is accurate. Generally, these results demonstrate that the Tb³⁺/TAPOF based ratiometric fluorescent sensor has an extensive application prospect in ciprofloxacin determination in the aquatic product industry.