Entrapment of magnetic nanoparticles into poly(divinylbenzene-co-N-vinylpyrrolidone) copolymer for the determination of prohibited and restricted fragrance ingredients in cosmetic products

In this work, a magnetic composite made by cobalt ferrite (CoFe2O4) magnetic nanoparticles entrapped into a poly(divinylbenzene-co-N-vinylpyrrolidone) copolymer is used to determine recently prohibited and restricted fragrances (i.e., Lilial, Lyral, and methyl-N-methylanthranilate) in cosmetics. This hydrophilic-lipophilic balance type material was characterized by magnetism measurements, scanning electron microscopy, nitrogen adsorption–desorption isotherms, and thermogravimetric analysis. The proposed method is based on stir bar sorptive dispersive microextraction (SBSDME) followed by gas chromatography coupled to mass spectrometry (GC–MS). The main quantitative parameters involved in the SBSDME were optimized by using a Box-Behnken design, whereas the desorption solvent was optimized by using a Simplex-Centroid design. Under the optimized conditions, good analytical features were obtained, showing good linearity (at least up to 200 ng mL−1), enrichment factors from 18 to 26, method limits of detection in the low µg/g range (0.01–0.1 µg g−1), and good intra- and inter-day repeatability (relative standard deviations below 10 %). Matrix effects were negligible as long as no more than 0.1 and 0.25 g of fat- and water-soluble samples, respectively, were weighed and diluted to 25 mL. Finally, the proposed method was successfully applied to three commercial cosmetic samples of different formulation, and quantitative relative recovery values (76–108 %) were obtained by external calibration. This work expands the analytical potential of SBSDME to the use of new magnetic polymer-based sorbents. In addition, it contributes to the availability of methods to ensure the safety of cosmetic products through quality control by means of a green methodology.