Simultaneous quantitation of perfluoroalkyl acids in human serum and breast milk using on-line sample preparation by HPLC column switching coupled to ESI-MS/MS

A high throughput analytical method using a column switching high-performance liquid chromatography combined with isotope dilution tandem mass spectrometry (column switching-HPLC–MS/MS) was developed to simultaneously quantitate the concentrations of 7 perfluoroalkyl acids (PFAAs) in serum and 3 PFAAs in breast milk samples. The sample preparation includes addition of the isotope-labelled internal standard solution to breast milk and serum, enzymatic hydrolysis and filtration of milk samples, precipitation of proteins and analysis by column switching-HPLC–MS/MS. The limits of quantitation ranged from 0.1 to 0.4 μg/l for serum and 0.02 to 0.15 μg/l for breast milk samples. The method accuracies ranged between 73.2% and 100.2% for the different analytes at two concentrations in PFAAs spiked samples. The validity of the method was confirmed by analysing 20 serum and 20 breast milk samples.