Comprehensive two-dimensional gas chromatography of polybrominated diphenyl ethers

Comprehensive two-dimensional gas chromatography with micro electron-capture detection (GC × GC–μECD) was evaluated for the separation of 125 polybrominated diphenyl ethers (PBDEs). From among the six column combinations that were evaluated, DB-1 × 007-65HT was found to be the most suitable because of: (i) the highest number of BDE congeners separated; (ii) the least decomposition of higher brominated congeners; and (iii) the most suitable maximum operating temperature. The separation of the 125 BDE congeners from five hydroxy- and two methoxy-BDEs and nine other brominated flame retardants (polybrominated biphenyls, tetrabromobisphenol-A, methyl-tetrabromobisphenol-A and hexabromocyclododecane) was also studied. Fluorinated BDEs were found to be valuable internal standards for the determination of BDEs because of their very similar physico-chemical properties and excellent separation from the parent BDEs, mainly in the second dimension. GC × GC–time-of-flight MS and GC × GC–μECD were shown to be useful tools to identify decomposition products of nona- and deca-substituted BDEs, which are formed during the GC run. Three nona-BDEs were shown to be the major decomposition products of BDE 209.