Environmental Chemistry Laboratory, California Department of Toxic Substances Control, Berkeley, CA 94710, USA.
Rapid Commun Mass Spectrom. 2013 Jul 15;27(13):1437-49. doi: 10.1002/rcm.6588.
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.
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.
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.
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.
对无处不在的阻燃剂对健康产生不良影响的担忧激发了我们对开发一种用于各种样品基质中这些有毒化合物的灵敏可靠分析方法的兴趣。本研究专注于研究十三种新型卤代阻燃剂的碎片途径和目标离子的结构。
在这项研究中，我们使用气相色谱（GC）/高分辨率双聚焦扇形质谱来表征这些新型阻燃剂的碎片途径。除了同位素模式外，还获得了准确的质量数据来验证分子公式。
根据键的断裂类型，将碎片途径分类，例如σ键断裂、α键断裂和带有氢转移的多重键断裂。α键断裂发生在 1,2-双-(2,4,6-三溴苯氧基)乙烷、烯丙基 2,4,6-三溴苯醚（ATE）、2,3-二溴丙基 2,4,6-三溴苯醚（DPTE）和 2-溴烯丙基 2,4,6-三溴苯醚（BATE）之间。ATE、BATE 和六氯环戊二烯基二溴环辛烷（HCDBCO）谱中的主导峰群对应于两个片段，这两个片段通过准确的质量数据和同位素模式证明。这两个片段是由于自由基损失和氢转移的两种竞争碎片途径形成的。其他化合物的碎片途径很复杂，涉及多个键的断裂和氢转移。
基于精确质量的 GC/MS 方法为持久性有机污染物的定量分析提供了极大的选择性和灵敏度。因此，碎片结构的阐明对于建立基于精确质量的同位素方法至关重要。此外，本研究对于 GC/MS/MS 方法的开发很有用，因为可以根据这些碎片模式轻松阐明前体离子和产物离子的多重反应监测（MRM）转换。
