Feasibility of GC-NCI-MS for the trace determination of tri- to deca- brominated diphenyl ethers in human samples

During recent years, a marked increase in the levels of brominated flame retardants (BFRs), especially polybrominated diphenyl ethers (PBDEs), in human tissues all over the world have been observed (Scheter et al., 2000; Tomsen et al., 2002). It is mainly due to the following facts: their production and use have undergone a dramatic increase starting in the 1980s (Sjödin et al., 2004) and their persistence and lipophilic character which tend to concentrate in the food chain, and thus accumulate in the human body (de Wit, 2002). The consumption in European countries of the different PBDE commercial mixtures available was estimated to be 150 metric tons of Penta-, 400 metric tons of Octaand 7000 metric tons of Deca-BDE technical products (BSEF, 2000), which made the higher brominated PBDEs, mainly the PBDE 209, a matter of special concern in European countries. However, the majority of the data available in the literature are focused on tetrato hexa-BDE congeners while little information is available on PBDEs 183 and 209 (the major components of the commercial flame retardant mixture Octa-BDE and Deca-BDE, respectively). In the same way, the concentrations concerning impurities of technical formulations and/or degradation products of PBDE 209, such as PBDEs 184, 191, 196, and 197 (Dandenourd et al., 2001; Stapleton et al., 2003), are very scarce in the literature. This fact could be related to the determination difficulties for high brominated PBDEs mainly when gas chromatography coupled with low resolution mass spectrometry (GC-MS) is used. GC-MS is a more selective technique than GC coupled to electron capture detector (ECD) but electron impact-MS (EIMS) ionisation mode is less sensitive than GC-ECD. In this direction, negative chemical ionisationMS (NCI-MS) operating mode has emerged as a valuable and more sensitive technique than EI-MS for the determination of PBDEs, mainly those with high bromination degree. On the other hand, human serum, umbilical cord serum, breast milk, and placenta samples are non-destructive matrices adequate for monitoring human exposure to PBDEs indicating both parents and neonates body burden. Although there is a wide knowledge on organochlorine contaminants in human tissues like serum and breast milk (Costopoulou et al., 2006; Chen et al., 2006), information regarding PBDE concentrations, mainly those of high-brominated congeners, in this kind of samples, is still very scarce in the literature. We present here, for the first time, PBDE levels, including trito decasubstituted congeners, found in human samples from the Spanish population. The preliminary results of an extended study of PBDE concentrations in paternal, maternal and neonate serum, breast milk, and placenta samples from individuals living in the Community of Madrid (Spain) are shown.