QuEChERS with Magnetic Hydrophilic–Lipophilic Balanced Adsorbent and Its Application in Multi-Class Veterinary Residues in Milk by Ultra High-Performance Liquid Chromatography-Tandem Mass Spectrometry

Abstract

Using magnetic hydrophilic–lipophilic balanced adsorbent (HLB), with divinylbenzene n-vinylpyrrolidone polymer as monomers and Fe3O4@C nanoparticles as magnetic material, a modified quick, easy, cheap, effective, rugged and safe (QuEChERS) method is proposed for veterinary residue analysis in milk. The magnetic Fe3O4@C-HLB adsorbent was fabricated via simple co-mixing method based on an “aggregate wrap” mechanism, which enabled magnetic solid-phase extraction. Thus, the resultant material can be separated from the solvent rapidly and conveniently by a magnet. The residues of regulatory interest in milk include β-lactams, aminoglyside, and macrolides. The analytes were quantified by ultra high-performance liquid chromatography coupled to an electrospray ionization tandem mass spectrometer operating in multiple reaction monitoring modes. The decision limit (CCα) was 0.1–0.8 µg/L, and the detection capability (CCβ) was 0.2–2 µg/L. The method was accurate with recoveries ranging from 70.5 to 98%. Good intra-precision and intermediate precision were obtained with RSD better than 10%.