title: Mass spectrometric characterization of halogenated flame retardants.
abstract: BACKGROUND
  Concerns about the adverse health effects of ubiquitous flame retardants spurred our interest in the development of a sensitive and reliable analytical method for these toxic compounds in various sample matrices. This study focuses on the investigation of fragmentation pathways and the structures of target ions of thirteen new halogenated flame retardants.
  
  
  METHODS
  In this study, we use gas chromatography (GC)/high-resolution double-focusing sector mass spectrometry to characterize the fragmentation pathways of these new flame retardants. Along with the isotope patterns, accurate mass data were acquired to verify the molecular formula.
  
  
  RESULTS
  The fragmentation pathways are classified based on the types of bond dissociations, e.g. σ-bond cleavage, α-bond cleavage and multiple-bond dissociations with a hydrogen shift. The α-bond dissociation occurs among 1,2-bis-(2,4,6-tribromophenoxy)ethane, allyl 2,4,6-tribromophenyl ether (ATE), 2,3-dibromopropyl 2,4,6-tribromophenyl ether (DPTE) and 2-bromoallyl 2,4,6-tribromophenyl ether (BATE). The peak clusters that dominated ATE, BATE and hexachlorocyclopentenyl-dibromocyclooctane (HCDBCO) spectra correspond to two fragments as proved by accurate mass data and isotope patterns. These two fragments are formed as the result of two competing fragmentation pathways of radical loss and hydrogen shift. Fragmentation pathways of the other compounds are complex, involving cleavage of multiple bonds and hydrogen shifts.
  
  
  CONCLUSIONS
  The accurate-mass-based GC/MS method offers great selectivity and sensitivity for quantitative analysis of the persistent organic pollutants. Thus, elucidation of the structures of the fragments is of prime importance for building an accurate-mass-based isotopic method. In addition, this study is useful for GC/MS/MS method development because multiple reaction monitoring (MRM) transitions of precursor ions and product ions may be easily elucidated based on these fragmentation patterns.
authors.affiliation: Environmental Chemistry Laboratory, California Department of Toxic Substances Control, Berkeley, CA 94710, USA. tguo@dtsc.ca.gov
authors.forename: Tan
authors.initials: T
authors.lastname: Guo
authors.forename: Bruce
authors.initials: B
authors.lastname: LaBelle
authors.forename: Myrto
authors.initials: M
authors.lastname: Petreas
authors.forename: June-Soo
authors.initials: JS
authors.lastname: Park
mesh_terms: D004784:Environmental Monitoring / Q000379:methods*; D005411:Flame Retardants / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D054879:Halogenation
chemical_list: D005411:Flame Retardants