Simultaneous determination of sixteen industrial pollutants in infant formula milk powder by dispersive solid phase extraction coupled with ultra-high performance liquid chromatography-tandem mass spectrometry

Abstract

A sensitive and high-throughput method based on dispersive solid phase extraction (dSPE) coupled with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was developed for the simultaneous determination of sixteen industrial pollutants in infant formula milk powder. A two-step extraction method, direct extraction with acetonitrile followed by salting out-acetonitrile extraction, was adopted in the extraction of target analytes in milk powder. After that, the extraction solution was concentrated and subsequently purified by dSPE. Sixteen target analytes were separated on a Phenomenex kinetex C18 column with the mobile phase of a mixture of methanol and 5 mmol L⁻¹ ammonium acetate water solution, detected by MS/MS under multiple reaction monitoring and quantified by an internal standard method. The method was validated in terms of the sensitivity, linearity, recovery and precision, and matrix effect. The results indicated that favorable linear relations (r > 0.99) were obtained for all analytes at their respective concentration ranges and their limits of quantification (LOQs, S/N = 10) were in the range of 0.02–0.80 μg kg⁻¹. The mean recoveries were calculated at three spiked levels and the values were found between 80.4 and 114% with relative standard deviation (RSD, n = 6) ranging from 3.0–12.2% and the inter-day precision (n = 5) ranging from 6.2–13.0%. The developed method is accurate and rapid and suitable for the simultaneous determination of bisphenols, alkylphenols and perfluorinated compounds in infant formula milk powder.