Analysis of hydroxylated polybrominated diphenyl ether metabolites by liquid chromatography/atmospheric pressure chemical ionization tandem mass spectrometry (original) (raw)

2010, Rapid Communications in Mass Spectrometry

Hydroxylated polybrominated diphenyl ether (OH-PBDEs) metabolites have the potential to cause endocrine disruption as well as other health effects. Currently, gas chromatography/mass spectrometry (GC/MS) after derivatization is used for the analysis of OH-PBDEs. However, there is a need for the direct analysis of OH-PBDEs at relatively low concentrations in environmental and biological samples. Liquid chromatography with atmospheric pressure chemical ionization tandem mass spectrometry (LC/APCI-MS/MS) was evaluated for the analysis of nine OH-PBDEs, ranging from tri-to hexabrominated. Separation of the nine isomeric metabolites was achieved with reversedphase liquid chromatography, followed by detection by APCI-MS in negative mode. Notably, a significant decrease in ionization was observed in 6-hydroxyl-substituted PBDE metabolites in the presence of an ortho-substituted bromine, relative to the other hydroxylated metabolites. This is probably due to the formation of dioxins in the source as a result of the high-temperature conditions, which prevented ionization by hydrogen abstraction. The MS/MS experiments also provided evidence of the neutral losses of HBr and Br 2 , indicating the possible use of neutral loss scanning and selected reaction monitoring (SRM) for the screening of brominated metabolites in samples. The applicability of LC/APCI-MS/MS was demonstrated for the analysis of metabolites of BDEs 47 and 99 formed in human liver microsomes. The LC/APCI-MS/MS method was able to detect metabolites that had previously been identified by GC/MS following derivatization. Analysis of OH-PBDEs by LC/APCI-MS/MS 2229 Product ions (m/z) 6-hydroxy-2,3,3',4,4',5'-hexabromodiphenyl ether 33.77 654, 656, 658, 660 573, 575, 577, 579, 581, 495, 497, 499, 501, 503 6-OH-BDE157