[Simultaneous determination of perfluoric acid, perfluorooctane sulfonic acid, bisphenol A, nonylphenol in infant milk powder by high-performance liquid chromatography-tandem mass spectrometry]

A rapid confirmative method was developed for determining the residues of perfluoric acid (PFOA), perfluorooctane sulfonic acid (PFOS), bisphenol A (BPA), and nonylphenol (NP) in infant milk powder by HPLC-MS/MS. The sample was dissolved in water by ultrasonication, and the protein was removed by dissolving in acetonitrile. The analytes were separated on a Hypersil GOLD C₁₈ column (150 mm×2.0 mm, 5 μm) using 30 mmol/L ammonium acetate solution and methanol as mobile phases, with gradient elution at a flow rate of 0.3 mL/min. Finally, the samples were determined by HPLC-MS/MS. Internal matrix-matched calibration was used for quantification. The limits of quantification (LOQs, S/N=10) of PFOA, PFOS, BPA, and NP were 0.5, 1.0, 10.0, and 5.0 μg/kg, respectively. The recoveries ranged from 86.1% to 106.8%, and the relative standard deviations (RSDs) were in the range from 2.87% to 9.53%. The method was also applied to real samples. The results showed that the method was simple and accurate, and can be used for determining the residues of PFOA, PFOS, BPA, and NP in infant milk powder.