Extraction of four endocrine-disrupting chemicals using a Fe3O4/graphene oxide/di-(2-ethylhexyl) phosphoric acid nano-composite, and their quantification by HPLC-UV

Abstract A Fe3O4/graphene oxide/di-(2-ethylhexyl) phosphoric acid nano-composite was prepared and characterized using the several techniques. The prepared nano-composite was employed as an innovative adsorbent for magnetic solid-phase extraction (MSPE) of phenol, bisphenol A, methyl paraben, and propyl paraben. After elution of the pre-concentrated analytes from the adsorbent surface, their quantification was carried out by high-performance liquid chromatography with UV-detection (HPLC-UV). The optimization of the several variables influencing the extraction efficiency was performed using a response surface methodology based on a central composite design. In the optimal conditions, calibration plots were linear in the concentration range of 10.0‒5000.0 ng L−1 for bisphenol A, methyl paraben, and propyl paraben, and 50.0‒5000.0 ng L−1 in the case of phenol. The detection limits and enrichment factor were in the range of 2.5‒14.3 ng L−1 and 500, respectively. The applicability of the MSPE-HPLC method for the determination of the target analytes was assessed by their quantification in human breast milk, urine and bottled water samples. In the case of the spiked samples, the relative recovery values, and the relative standard deviations were in the range of 97.67–104.00%, and 1.02–7.94%, respectively.