Simultaneous determination of organophosphorus and brominated flame retardants and polychlorinated biphenyls in hair by pressurized liquid extraction and gas chromatography/tandem mass spectrometry

Polybrominated diphenyl ethers (PBDEs), brominated flame retardants widely used since the 1980s, were banned or phased out in many countries during the 2000s and gradually replaced by organophosphorus flame retardants (OPFRs), substances for which few exposure data are available to date. Like phthalates, these OPFRs are used as additives in many materials without being chemically bound and can therefore easily be released into the environment by abrasion and/or volatilization. Exposure to these substances can be assessed indirectly via their measurement in different environmental matrices or directly via the measurement of the population impregnation. In this context, a method for the determination of selected OPFRs but also PBDEs and PCBs in human hair samples was developed. The protocol includes a pulverization step of the hair sample followed by an automated pressurized liquid extraction (PLE) step, and finally by a targeted quantitative analysis by gas chromatography coupled to tandem mass spectrometry (GC/MS/MS). The proposed analytical method allows the determination of 37 substances among which 8 PBDEs, 11 PCBs and 15 OPFRs including tributyl phosphate (TBP), tris(2-chloroethyl) phosphate (TCEP), tris(1-chloro-2-propyl) phosphate (TCPP), tris(1,3-dichloro-2-propyl) phosphate (TDCPP), 2-ethylhexyl diphenyl phosphate (EHDPP) and triphenyl phosphate (TPP), with limits of quantification, for a 25-mg hair sample, ranging from 2 ng/g for triisopropyl phosphate (TiPP) to 400 ng/g for TCPP. The performance of the method was then assessed (several operators and days of analysis) on an inert material (Celite® 545) unspiked and spiked at the LOQ level and at a level 10 times higher than the LOQ, on a non-contaminated real human hair sample unspiked and spiked at a level 10 times higher than the LOQ, and via replicate analysis of the standard reference material SRM 2585 (Organic Contaminants in House Dust), for which indicative, reference or certified concentrations are available for some PBDEs, PCBs and OPFRs. The results obtained were very satisfactory in terms of interday method precision (< 25% in most cases) and accuracy (between 70 and 130% for most substances).