Simultaneous selective enrichment of methylparaben, propylparaben, and butylparaben from cosmetics samples based on syringe-to-syringe magnetic fluid phase microextraction.

Present work is the preparation of novel magnetic nanofluids based on deep eutectic solvent and used for the rapid microextraction of methylparaben (MP), propylparaben (PP), and butylparaben (BP) from cosmetics samples using syringe-to-syringe dispersive magnetic nanofluid microextraction procedure (SS-DMNF-ME). The optimization of the extraction of MP, PP, and BP was performed through central composite design (CCD). The optimum extraction conditions were assessed by optimizing pH, nanofluid volume, NaCl concentration, cycle number, and methanol volume. pH 8.0, 200 μL of magnetic nanofluid, 6% w/v of NaCl, eight cycles of injection/back injection, and 80 μL of methanol were the optimum extraction conditions, with the maximum recoveries of 98.62%, 100.92%, and 99.13% for MP, PP, and BP, respectively. The figures of merit calculated under the optimum condition were achieved from the CCD, and the developed method exhibited the low limits of quantitation (4.3, 3.0, and 2.7 ng mL) and detection (1.3, 0.9, and 0.8 ng mL) for MP, PP, and BP, respectively, as well as excellent linearity with R > 0.99. The relative recoveries of three parabens in the actual samples were 85.99-99.07% with relative standard deviations ≤5.52%. In comparison to other extraction methods, SS-DMNF-ME was readily and rapidly determined MP, PP, and BP using HPLC-UV, and experimental data showed the efficiency, robustness, and reliability of the proposed method.