Automated solid-phase extraction for the determination of polybrominated diphenyl ethers and polychlorinated biphenyls in serum--application on archived Norwegian samples from 1977 to 2003

An analytical method comprised of automated solid-phase extraction and determination using gas chromatography mass spectrometry (single quadrupole) has been developed for the determination of 12 polybrominated diphenyl ethers (PBDEs), 26 polychlorinated biphenyls (PCBs), two organochlorine compounds (OCs) (hexachlorobenzene and octachlorostyrene) and two brominated phenols (pentabromophenol, and tetrabromobisphenol-A (TBBP-A)). The analytes were extracted using a sorbent of polystyrene-divinylbenzene and an additional clean-up was performed on a sulphuric acid-silica column to remove lipids. The method has been validated by spiking horse serum at five levels. The mean accuracy given as recovery relative to internal standards was 95%, 99%, 93% and 109% for the PBDEs PCBs, OCs and brominated phenols, respectively. The mean repeatability given as RSDs was respectively 6.9%, 8.7%, 7.5% and 15%. Estimated limits of detection (S/N=3) were in the range 0.2-1.8 pg/g serum for the PBDEs and phenols, and from 0.1 pg/g to 56 pg/g serum for the PCBs and OCs. The validated method has been used to investigate the levels of PBDEs and PCBs in 21 pooled serum samples from the general Norwegian population. In serum from men (age 40-50 years) the sum of seven PBDE congeners (IUPAC No. 28, 47, 99, 100, 153, 154 and 183) increased from 1977 (0.5 ng/g lipids) to 1998 (4.8 ng/g lipids). From 1999 to 2003 the concentration of PBDEs seems to have stabilised. On the other hand, the sum of five PCBs (IUPAC No. 101, 118, 138, 153 and 180) in these samples decreased steadily from 1977 (666 ng/g lipids) to 2003 (176 ng/g lipids). Tetrabromobisphenol-A and BDE-209 were detected in almost all samples, but no similar temporal trends to that seen for the PBDEs were observed for these compounds, which might be due to the short half-lives of these brominated flame retardants (FR) in humans.