Metal–organic framework UiO-66 modified magnetite@silica core–shell magnetic microspheres for magnetic solid-phase extraction of domoic acid from shellfish samples

Fe 3 O 4 @SiO 2 @UiO-66 core–shell magnetic microspheres were synthesized and characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectrometry, vibrating sample magnetometry, nitrogen adsorption porosimetry and zeta potential analyzer. The synthesized Fe 3 O 4 @SiO 2 @UiO-66 microspheres were first used for magnetic solid-phase extraction (MSPE) of domoic acid (DA) in shellfish samples. Combined with high performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS), a fast, simple and sensitive method for the determination of DA was established successfully. Under the optimized conditions, the developed method showed short analysis time, good linearity ( r 2   =   0.9990), low limit of detection (1.45   pg   mL −1 ; S/N   =   3:1), low limit of quantification (4.82   pg   mL −1 ; S/N   =   10:1), and good extraction repeatability (RSD   ≤   5.0%; n   =   5). Real shellfish samples were processed using the developed method, and trace level of DA was detected. The results demonstrate that Fe 3 O 4 @SiO 2 @UiO-66 core–shell magnetic microspheres are the promising sorbents for rapid and efficient extraction of polar analytes from complex biological samples.