Effective Extraction of Domoic Acid from Seafood Based on Postsynthetic-Modified Magnetic Zeolite Imidazolate...

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.