Determination of polybrominated diphenyl ethers in human milk samples in the Czech Republic: Comparative study of negative chemical ionisation mass spectrometry and time-of-flight high-resolution mass spectrometry

In the Czech Republic no study on the levels of brominated flame retardants in human milk has been conducted, yet. In the first step analytical method for determination of PBDEs in this bioindicator matrix was implemented. Liquid–liquid extraction (LLE) (hexane, diethyl ether), followed by gel permeation chromatography was employed for isolation of PBDEs. Identification and quantification of PBDEs was carried out by GC–MS operated in negative chemical ionisation (NCI). Two mass spectrometric technologies, one employing quadrupole and the other one high resolution (HR) time-of-flight (TOF) analyzer, etc. were used in our study. Detection limits (LODs) obtained by quadrupole analyzer ranged from 0.02 to 0.05 ng g⁻¹ lipid weight, using high resolution time-of-flight analyzer LODs were significantly lower, ranging from 0.002–0.005 ng g⁻¹ lipid weight, what enabled detection of minor PBDE congeners.

Within this pilot study 103 breast milk samples, obtained from mothers living in Olomouc region, were examined. Ten PBDE congeners were determined. All samples examined till now contained PBDEs residues, the dominating contaminant representing this group was congener BDE 47. In most of analysed samples levels of this compound ranged from 0.2 to 2 ng g⁻¹ of lipid weight. Three exceptionally contaminated samples, containing levels of PBDEs 5–10 times higher than other samples, were found.