Determination of PBDEs in human breast adipose tissues by gas chromatography coupled to triple quadrupole mass spectrometry

Abstract

The potential of gas chromatography / tandem mass spectrometry with triple quadrupole analyzer for determination of 12 polybrominated diphenyl ethers in human breast tissues has been investigated. After extraction with hexane, two purification procedures -automated normal-phase HPLC and solid phase extraction – were assayed. Both electron impact ionization, in selected reaction monitoring mode, and negative chemical ionization, in selected ion recording mode, were tested for the optimum determination of analytes. Isotopically labelled standards were added before extraction as surrogates: [13C] BDE47, [13C] BDE99 and [13C] BDE153 for EI, and p,p’-DDE-D8 for NCI. The method was validated in terms of accuracy, precision, limits of detection and limits of quantification, using human breast tissue spiked at three levels in the range 1-50 ng/g (5-250 ng/g for BDE 209). The analytical approach using SPE clean-up followed by GC-MS (NCI) led to lower detection limits (0.006-2 ng/g) and allowed the determination of the most problematic congener, BDE 209, whose poor sensitivity made difficult its determination at low residue levels. Special attention was given to the confirmation of the compounds detected in samples in order to avoid reporting false positives. Two MS/MS transitions or three m/z ions were selected for each analyte when using EI or NCI modes, respectively. In both cases, the transition/ion intensity ratio was used as confirmation parameter. The developed methodology was applied to the analysis of real human samples. Several BDEs (BDEs congeners 47, 100, 99, 154, 153 183 and 209) were detected in the range of 0.08-0.23 ng/g