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Low-density solvent-based dispersive liquid–liquid microextraction coupled with hydrophobic magnetic nanoparticles for determination of synthetic phenolic antioxidants in vegetable oils by high-performance liquid chromatography

ABSTRACT A novel and rapid low-density solvent-based dispersive liquid–liquid microextraction technique combined with magnetic solid-phase extraction (MSPE) was developed for preconcentration and separation of synthetic phenolic antioxidants (SPAs) in vegetable oils prior to high-performance liquid chromatography. 1-Heptanol was used as extractant and decanoic acid@Fe3O4 nanoparticles (DA@Fe3O4 NPs) as carrier to retrieve and separate the 1-heptanol. In that manner, the upper extractant containing the SPAs is the target of the MSPE step rather than the SPAs directly. Thanks to the interaction between carboxyl group present on the surface of the magnetic nanoparticles and the alcohol functional group of the extractant, the DA@Fe3O4 NPs facilitates the recollection of the 1-heptanol after extraction. The main parameters affecting the extraction recoveries of four SPAs were investigated, and the proposed method provided a good linearity in the range of 50–2000 ng mL−1, low limits of detection (1.2–5.8 ng mL−1), and good repeatability of the extractions (relative standard deviations ≤6.7%, n = 5), and recoveries were ranged from 90.2% to 99.5%.