Identification of the Novel Cycloaliphatic Brominated Flame Retardant 1,2-Dibromo-4-(1,2-dibromoethyl)cyclohexane in Canadian Arctic Beluga (Delphinapterus leucas)

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• 作者：Gregg T. Tomy ; Kerri Pleskach ; Gilles Arsenault ; Dave Potter ; Robert McCrindle ; Chris H. Marvin ; Ed Sverko ; Sheryl Tittlemier
• 刊名：Environmental Science & Technology
• 出版年：2008
• 出版时间：January 15, 2008
• 年：2008
• 卷：42
• 期：2
• 页码：543 - 549
• 全文大小：173K
• 年卷期：v.42,no.2(January 15, 2008)
• ISSN：1520-5851

文摘

1,2-Dibromo-4-(1,2-dibromoethyl)cyclohexane (TBECH) is used primarily as an additive flame retardant. Technical grade TBECH consists of near equimolar amounts of two (of a possible four) diastereoisomers: rac-(1R,2R)-1,2-dibromo-(4S)-4-((1S)-1,2-dibromoethyl)cyclohexane (α-TBECH) and rac-(1R,2R)-1,2-dibromo-(4S)-4-((1R)-1,2-dibromoethyl)cyclohexane (β-TBECH). The two other possible isomers, γ- and δ-TBECH, appear in the technical mixture when heated at temperatures above 120 °C. Careful selection of GC-capillary column length was critical in resolution of the two main diastereoisomers. Column lengths of 60 or 30 m (0.25 µm film thickness) resulted in incomplete separation of the α- and β-isomers, while on a 10 m column, the isomers were baseline separated. The γ- and δ-isomers could not be resolved on any column length in this study. Increased injector port temperature induced thermal conversion of the α- and β-isomers to γ- and δ-TBECH. Electron impact ionization (EI) was used to provide specificity because no characteristic ions in the electron capture negative ionization (ECNI) mass spectrum of TBECH were evident. In EI, the dominant ions in the mass spectrum corresponded to a concomitant loss of HBr and Br from the molecular ion; the biggest peak in this ion cluster (m/z 266.9208) was used for quantitation and the second biggest peak (m/z 264.9227) was used for confirmation. Beluga (Delphinapterus leucas) blubber extracts of animals from the Canadian Arctic (n = 29) were analyzed using low resolution (LR) MS and high resolution (HR) MS run at a resolving power of 10 000. β-TBECH was the only isomer observed in the samples and was detected in 17 samples. The LRMS technique appeared to overestimate β-TBECH concentrations compared to HRMS, suggesting a small interference arose at the nominal mass monitored. This potential interference also led to some false positive and negative values (n = 7) based on the expected ion ratio of the quantitation and confirmation ions. Observed concentrations of the β-isomer as measured by HRMS ranged from 1.1 to 9.3 ng/g (lipid weight).