Vortex-assisted hollow-fiber liquid-phase microextraction coupled with high performance liquid chromatography for the determination of three synthetic endocrine disrupting compounds in milk

In this study, a vortex-assisted three-phase hollow fiber liquid-phase microextraction (VA-HF-LPME) coupling with high performance liquid chromatography (HPLC) method was developed for determination of three synthetic endocrine disrupting compounds[EDCs, bisphenol-A (BPA), bisphenol-AF (BPAF) and tetrabromobisphenol-A (TBBPA)] in milk samples. Vortex provided effective and mild mixing of the sample solution and increased the contact between analytes and boundary layers of the hollow fibre, thereby enhancing mass transfer rate and leading to high extraction efficiency of the target analytes. The influencing parameters of VA-HF-LPME sample preparation method, such as organic solvents (acceptor phase), pH of sample solution (donor phase), sample volume, concentration of NaOH, extraction time, and ionic strength were systematically optimized. The instrumental calibration curves of BPA, BPAF and TBBPA show good linear relations (R² > 0.9988) in the concentration range of 0.5-200, 0.5-200 and 1.0-250 µg L-1, respectively. The relative standard deviations (RSD, n = 5) were 1.3-3.7%. The limits of detection (LOD, S/N = 3) were in the range of 0.16-0.35 µg L-1 and the limits of quantification (LOQ, S/N = 10) were in the range of 0.51-1.12 µg L-1. The proposed method was successfully applied to the extraction of EDCs in milk samples.