17th International Mass Spectrometry Conference :: Prague, 2006
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|Presentation date:||Thu, Aug 31, 2006|
|Presentation time:||14:30 – 16:00|
Laurent Debrauwer1, Anne Riu1, Ronan Cariou2, Jean-Philippe Antignac2, Bruno Le Bizec2, Daniel Zalko11 INRA - ENVT, Toulouse, France
Correspondence address: Laurent Debrauwer, INRA - ENVT, UMR 1089 Xenobiotiques, Chemin de Tournefeuille, 180, TOULOUSE, 31931 France.
Keywords: Environmental; Ionization, Atmospheric Pressure Photo-; Mass Spectrometry, High Resolution; MS/MS, Liquid Chromatography.
Novel aspect: Development of novel method for PBDE determination in adipose tissues using LC-MS.
Polybrominated diphenylethers (PBDEs) are among the most used brominated flame retardants (BFRs) in the production of polymers and plastics. Although they are widely spread in the environment, very few data is available about their fate in the environment and animals. GC-MS is at present the most often used analytical tool for the analysis of PBDEs. However, the analysis of highly brominated (octa- to deca-BDEs) is known to be difficult, owing mainly to thermal degradation problems. For these compounds, we have recently shown that LC-MS using atmospheric pressure photo-ionisation (APPI) could constitute a possible alternative to overcome these problems.1
In this work, PBDEs determination methods have been developed by both GC-MS (electron ionisation / high resolution detection), and LC-MS (APPI / ion trap tandem mass spectrometry) and applied to the analysis of human adipose tissue extracts. GC-MS analyses were carried out using a Jeol SX102-A double focusing electromagnetic mass spectrometer operating at a resolution of 10000. For the highly brominated PBDE congeners studied in this work, electron ionisation gave rise to [M-Br2]+. fragment ions which were monitored for octa, nona and deca-BDEs respectively. Very high sensitivity levels (10-500 ppt) could be reached by this method.2 However, the partial degradation of deca-BDE into octa- and nano-BDE congeners complicated the interpretation of quantitative data for these compounds.
A LCQ Deca XP ion trap mass spectrometer (Thermo Electron) was used for the analysis of highly brominated PBDE congeners by LC-APPI-MS. The APPI source was fitted with a Krypton lamp emitting 10eV photons. For congeners ranging from hepta- to deca-BDEs, the negative ion mode was found to be more appropriate. In these conditions, the formation of [M-Br+O]- ions was observed. From these ions, the elimination of HBr as well as the breakage of the PBDE ether bond were observed as the most intense diagnostic signals in MS/MS experiments. For deca-BDE, the limit of detection was reached for ca. 10 pg injected on column, which is very close to GC-MS limits. No contribution of deca-BDE degradation compounds was observed in the LC-MS trace obtained for octa- and nona-BDEs. However, the method suffered a lack of chromatographic resolution compared to capillary GC, and the separation of the various congeners remains to be improved. The development of both analytical methods will be presented and their respective performances will be discussed. The application of both GC-EI-HRMS and LC-APPI-MS/MS to the analysis of PBDEs in adipose tissue will also be shown.
1. L. Debrauwer et al., Proc. 53rd ASMS Conference, San Antonio, TX, June 5-9 (2005).
2. R. Cariou et al., J. Chromatogr. A 1100, 144 (2005).