A simple and fast method for the simultaneous determination of polychlorinated biphenyls and polybrominated diphenyl ethers in small volumes of human serum

A fast extraction and clean-up method for the simultaneous determination of PCBs and PBDEs has been developed. The procedure consisted of a solid-phase extraction (SPE) of the analytes on an Oasis® HLB cartridge and the subsequent on-line fat elimination by directly dropping the eluate from the SPE cartridge onto a second cartridge containing layers of activated neutral silica gel and sulphuric acid modified silica gel. Detection limits using a gas chromatography coupled with an ion trap detector in the tandem mass spectrometry mode were from 0.03 to 0.3 pg/μL for PCBs and from 0.07 to 1.3 pg/μL for PBDEs. Repeatability (lower than 11%) and reproducibility (lower than 17%), expressed as relative standard deviation (RSD, n = 4), were satisfactory. The feasibility of the method developed for the determination of the target compounds was evaluated by participation in several rounds of interlaboratory exercises involving human serum with a wide range of PBDE and PCB concentrations. The method has been applied to the evaluation of PBDEs and PCBs in human serum samples of up to 1 mL.