The determination of estrogens in fish samples by magnetic solid phase extraction coupled to high performance liquid chromatography-diode array detector

In this work, a novel magnetic nanoparticle (Fe₃O₄@SiO₂@MIL-53(Al)-NH₂) constructed on the basis of metal-organic frameworks (MOFs, MIL-53(Al)-NH₂) was prepared, which was characterized by Fourier transform infrared spectroscopy (FT-IR), transmission electron microscope (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Good preparation reproducibility was obtained with the relative standard deviations (RSDs) ranging from 6.6 to 13.1 % (n = 6). In addition, the prepared Fe₃O₄@SiO₂@MIL-53(Al)-NH₂ possesses many merits, including simple preparation, greenness, good water/solvent stability and high specific surface area. The Fe₃O₄@SiO₂@MIL-53(Al)-NH₂ was used as an adsorbent for magnetic solid phase extraction (MSPE) of estrogens in fish samples. To achieve higher extraction efficiency, several factors including extraction time, pH value, ionic strength and desorption time were explored. Compared with other methods, the developed method exhibits high extraction efficiency, fast extraction kinetics and suitable for simultaneous analysis of large number of samples. The method was successfully applied to the analysis of estrogens in (spiked) fish samples, and good recoveries were obtained.