Simultaneous use of gas chromatography/ion trap mass spectrometry - electron capture detector to improve the analysis of bromodiphenyl ethers in biological and environmental samples

Authors: WANG, DONGLI - UNIV OF HAWAII; ATKINSON, SHANNON - UNIV OF ALASKA FAIRBANKS; HOOVER-MILLER, ANNE - UNIV OF ALASKA FAIRBANKS; Shelver, Weilin; LI, QING - UNIV OF HAWAII

Submitted to: Rapid Communications in Mass Spectrometry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/19/2007
Publication Date: 2/1/2008
Citation: Wang, D., Atkinson, S., Hoover-Miller, A., Shelver, W.L., Li, Q.X. 2008. Simultaneous use of gas chromatography/ion trap mass spectrometry - electron capture detector to improve the analysis of bromodiphenyl ethers in biological and environmental samples. Rapid Communications in Mass Spectrometry 22(5):647-656.

Interpretive Summary: This research describes a new method for determining the concentration of a particular class of fire retardant (PBDE). Flame retardants are used in clothes, furniture, and electronic equipment like computers and TVs to prevent injury and death from fire. However, PBDE’s are found throughout the environment such as in soil, air, and water. More importantly, they have been detected in human blood and milk with the amounts of PBDEs found in North Americans increasing dramatically in past years. Through the years, manufacturers have shifted the types of PBDE’s they use and the analytical techniques must be able to measure these new types as well as the older types. Because the PBDEs resemble some chemicals that have been proven harmful, we are concerned about their wide occurrence and need methods that can accurately measure these compounds in a variety of matrices such as fat, dust, and soil. The research described is an effort to broaden the types of PBDE’s that can be accurately measured in one experiment and thus decrease the cost and broaden the scope of this type of analysis with instruments that are more affordable than those that are used currently.

Technical Abstract: The mass range limit of some gas chromatograph/mass spectrometers (GC/MS) prohibits the sensitive analysis of higher brominated diphenyl ethers (BDEs). A gas chromatograph/electron capture detector (GC/ECD) can sensitively determine higher BDEs. In this study, a method that GC eluents were split with a post column splitter into an ECD and ion trap mass spectrometer (ITMS) (1:10, ECD:ITMS) was developed to determine polybrominated diphenyl ethers (PBDEs) in biological and environmental samples. The ion trap temperatures, ionization mode, MS-MS parameters (e.g., excitation amplitude and stability parameter) were optimized for the quantitation of mono- to hepta-BDEs with stable isotopic dilution techniques, while ECD was used for the determination of octa- to deca-BDEs. After accelerated solvent extraction followed by silica gel and alumina column cleanup, average recoveries of PBDEs from spiked sand samples were 52-112% with relative standard deviations (RSDs) of 1-24% and those from spiked lard samples were 44-126% with RSDs of 7-26%. Average recoveries ranged from 51% to 130% for 13C-labeled PBDEs spiked in the real and matrix samples. The method detection limits were congener specific and were 0.18-120 pg/g of the PBDEs in animal tissue samples, and 0.56-17 pg/g in soil and indoor dust samples. Application of the method showed that the concentration of each PBDE congener ranged from not detected (nd) to 24 ng/g in the dry soil sample, nd-759 ng/g in the indoor dust, nd to 15 ng/g wet weight in the Alaskan harbor seals blubber sample, and nd to 16 ng/'L of the identified 24 of 42 breakdown products from BDE-209 after zerovalent iron treatment for 40 days. Results obtained by this method were comparable to those by GC/high resolution MS. GC/ECD-ITMS coupled with a short column (15 m) has successfully overcome the mass limitation of many GC/ITMSs on the market for the analysis of this emerging class of pollutants – PBDEs.