Fabrication and characterization of magnetic mesoporous nanoparticles for efficient determination and magnetic separation of sulfonamides in food samples.

A magnetic, mesoporous core/shell structured Fe 3 O 4 @SiO 2 @mSiO 2 nanocomposite was synthesized and employed as a magnetic solid phase extraction (MSPE) sorbent for the determination of trace sulfonamides (SAs) in food samples. The synthesized nanocomposite was characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, X-ray diffraction, N 2 sorption analysis and vibrating sample magnetometry. The results showed that Fe 3 O 4 @SiO 2 @mSiO 2 possessed a mesoporous structure with a large surface area. Batch experiments were carried out to investigate the adsorption ability for SAs. Fe 3 O 4 @SiO 2 @mSiO 2 showed fast kinetics and high adsorption capacity, and the pseudo-second-order model and Langmuir adsorption isotherm are well fitted with the experimental data, indicating that chemical adsorption might be the rate-limiting step. Moreover, the high adsorption capacity can be maintained for at least 8 runs, indicating excellent stability and reusability. The proposed method exhibited good linearity in the range of 0.2-500 μg L -1 , the R 2 values of all the analytes were greater than 0.99 and the LODs were all lower than 0.2 μg L -1 . Furthermore, real food samples were successfully analyzed with Fe 3 O 4 @SiO 2 @mSiO 2 and high recoveries varying from 89.7% and 110.6% were obtained with low relative standard deviations ranging from 1.78% to 6.91%. The Fe 3 O 4 @SiO 2 @mSiO 2 magnetic nanocomposite is a promising sorbent for the efficient extraction of SAs from complex food samples.