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.
Chuanhui Huang,Xuezhi Qiao,Weiming Sun,Hui Chen,Xiangyu Chen,Lan Zhang,Tie Wang
Domoic acid (DA) is a naturally occurring neurotoxin known to bioaccumulate in marine products. Despite its hypertoxicity, the enrichment and analysis of trace DA in complex marine organisms remains a challenge. We describe herein the fabrication of a postsynthetic-modified magnetic zeolite imidazolate framework-8 (Fe3O4 SPs@ZIF-8/Zn2+), based on Fe3O4 superparticles, for the adsorption of DA from complex biological matrices. The adsorption of DA is rapid (∼5 min) and occurs through strong electrostatic interactions and chelation with coordinatively unsaturated zinc sites on the surface of Fe3O4 SPs@ZIF-8/Zn2+. Employing our Fe3O4 SPs@ZIF-8/Zn2+ sorbent in a magnetic solid-phase extraction, followed by liquid chromatographic separation and tandem mass spectrometric detection, resulted in a facile, rapid, efficient, and sensitive method for the enrichment and detection of trace DA in marine products. After optimization, this method yielded satisfactory precision (relative standard deviation ≤3.4%; n = 5) with a high degree of linearity from 1.0 to 1000.0 pg mL–1 (r2 = 0.9997) and a detection limit of 0.2 pg mL–1 (S/N = 3). Recoveries of 93.1–102.3% were obtained in spiked aquatic products. In addition, trace levels of DA (49.2 pg mL–1) were found in shellfish samples, confirming the applicability of our Fe3O4 SPs@ZIF-8/Zn2+ adsorbent for the detection of DA in seafood.
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