Determination of 21 perfluoroalkyl substances and organophosphorus compounds in breast milk by liquid chromatography coupled to orbitrap high-resolution mass spectrometry.

The human exposure to perfluoroalkyl (PFASs) and organophosphorus (OPs) compounds is a cause of concern and its determination in biological matrices, including human milk, is an emergent approach for evaluate their exposure. A comprehensive strategy for the quantitative determination of 21 PFASs and OPs compounds in breast milk was developed. The proposed method includes an extraction and clean-up procedure based on the QuEChERs methodology followed by an ultra-high performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS) determination. The full-scan mass data were acquired with a resolution of 50000 FWHM and a mass accuracy better than 5 ppm. Method validation was performed in terms of recovery, repeatability, linearity and limit of quantification. The obtained recoveries varied between 70 and 120% with a precision (RSD) lower than 25%. The limit of quantification (LOQ) ranged between 1.9 and 19.0 ng g lipid weight for OPs, and between 0.066 ng mL and 0.666 ng mL for PFASs. A breast milk reference material was used in order to check the validated method. The developed analytical strategy was applied to 20 breast milk samples collected from mothers living in the Valencian Region (Spain). All of the OPs analyzed except tris(2-chloroethyl) phosphate (TCEP) were detected in at least one sample. In all samples, perfluoro-n-pentanoic acid (PFPeA), perfluoro-n-octanoic acid (PFOA) and sodium perfluoro-1-octanesulfonate (PFOS) were the most frequently detected analytes. Concentration of total OPs (∑OPs) and total PFASs (∑PFASs) ranged from 1.9 to 37.7 ng g lipid weight and from 0.066 to 0.356 ng mL, respectively.