Fe3O4@SiO2-BD-DADB-COF is proposed as a novel magnetic covalent organic framework for the determination and extraction of 15 macrolide antibiotics in water and honey

Abstract

In our research, an emerging magnetic covalent organic framework (Fe₃O₄@SiO₂-BD-DADB-COF) was formulated through Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), etc. Several parameters affecting the extraction process were refined. Accordingly, a novel method of determining 15 macrolides (MALs) in honey and water was established through the Fe₃O₄@SiO₂-BD-DADB-COF as a magnetic solid-phase extraction (MSPE) adsorbent and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). In consequence, the standard curves for the 15 MALs exhibited an exceptional linearity from 0.1 to 200 μg L^-1, and the correlation coefficients (R ²) varied from 0.9990 to 0.9999. The recoveries fell between 70.01% and 115.56%, with the relative standard deviations (RSDs) being below 9.93% (n = 5). The detection limits reached 0.001-0.075 μg L^-1 with the quantification limits being 0.004-0.228 μg L^-1. Ultimately, the method was excellently applied to the analysis of MALs in honey and water.

Fig. 1. Scheme illustration for preparation of Fe₃O₄@SiO₂–BD–DADB and the MSPE procedure.

Fig. 2. The SEM of (A) Fe₃O₄, (B) Fe₃O₄@SiO₂–BD–DADB-COF; the TEM of (C) Fe₃O₄, (D) Fe₃O₄@SiO₂–BD–DADB-COF.

Fig. 3. (A) FT-IR spectra of Fe₃O₄, Fe₃O₄@SiO₂ and Fe₃O₄@SiO₂–BD–DADB-COF; (B) XRD patterns of Fe₃O₄, Fe₃O₄@SiO₂ and Fe₃O₄@SiO₂–BD–DADB-COF; (C) N₂ adsorption–desorption isotherms of Fe₃O₄ and Fe₃O₄@SiO₂–BD–DADB-COF; (D) VSM curves of Fe₃O₄ and Fe₃O₄@SiO₂–BD–DADB-COF.

Fig. 4. Effect of (A) adsorbent dosage; (B) sample solution pH; (C) NaCl concentration; (D) extraction time.

Fig. 5. Effect of (A) elution solvents; (B) elution volume; (C) desorption time.