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

Abstract

Bromodiphenyl ethers (BDEs) are a class of synthetic flame retardants and are widely present in the environment. Analysis of higher BDE congeners has proven to be a challenge. We report the development of a method that enhances their analysis by splitting the eluent of a gas chromatograph (GC) between an electron capture detector (ECD) and an ion trap mass spectrometer (ITMS): 1:10, ECD:ITMS. This allowed the quantitation of the lower molecular weight (MW) BDE congeners (Br1-Br7) with the ITMS and of the higher MW BDEs (Br8-Br10) with the highly sensitive ECD. The IT temperature, ionization mode, and MS/MS parameters (excitation amplitude and stability parameter) were optimized. This method took the advantages of the best detector for the different BDE homologues and was suitable for the analysis of BDEs in environmental and biological samples. Average recoveries were 52-112% for BDEs from spiked sand samples and 57-126% from spiked lard samples after accelerated solvent extraction followed by silica gel and alumina column clean-up. Average recoveries ranged from 51% to 130% for 13C-labeled BDEs spiked in the real and in matrix samples. The method detection limits for specific congeners were 0.18-120 pg/g of the BDEs in animal tissue samples, and 0.05-40 pg/g in soil and indoor dust samples. The utility of the method was demonstrated by analyzing actual harbor seal blubber, indoor dust and soil samples. The concentration of each BDE ranged from non-detectable (nd) to 41 ng/g in the dry soil sample, nd to 1042 ng/g in the indoor dust, nd to 15 ng/g wet weight in the Alaskan harbor seal blubber sample, and 0.02 to 11 ng/microL of the identified 23 of the 42 breakdown products from BDE-209 after zerovalent iron treatment. Finally, an interlaboratory comparison showed high correspondence between the GC/ITMS-ECD method and a GC high-resolution MS system for the analysis of BDEs in soil samples.

Application of mass spectrometry in the analysis of polybrominated diphenyl ethers

“…PBDEs were detected in marine mammals such as hooded seals ( Cistophora cristata ) (Wolkers et al, 2006a,b), gray seals ( Halichoerus grypus ) and harbor seals ( Phoca vitulina ) from the Gulf of St. Lawrence, Sable Island and British Columbia of Canada, respectively (Ikonomou & Addison, 2008), harbor seals from Alaska's Kodiak Island (Wang et al, 2008a), ringed seals ( Phoca hispida ) in east and central west Greenland (Riget et al, 2006; Vorkamp et al, 2008) and free‐ranging spotted seals ( Phoca largha ) from Bristol Bay, Alaska (Neale et al, 2007). The other species include free‐ranging polar bears ( Ursus maritimus ) in Alaska, east Greenland, the Canadian Arctic and Norway's Svalbard (Muir et al, 2006; Soermo et al, 2006; Dietz et al, 2007; Gebbink et al, 2008), walruses ( Odobenus rosmarus ) from Svalbard (Wolkers et al, 2006b), California sea lions ( Zalophus californianus ) (Stapleton et al, 2006a), free‐ranging bottlenose dolphins ( Tursiops Truncatus ) from two southeast Atlantic estuarine areas (Fair et al, 2007), wild river otters ( Lontra canadensis ) (Basu, Scheuhammer, & O'Brien, 2007), and southern sea otters ( Enhydra lutris nereis ) along the coasts of California, Washington, and Alaska (USA), and Kamchatka (Russia) (Kannan et al, 2007, 2008).…”

Organic halogenated contaminants in mother–fetus pairs of harbor seals (Phoca vitulina richardii) from Alaska, 2000–2002

“…The GC was equipped with a 60 m ZB-l column (0.25 mm i.d., 0.25 µm film thickness) with a constant flow rate of (2 ml/min) of carrier gas (helium). The MS/MS methods were developed to analyze OCPs, PCBs, PCNs [24, 26] and PBDEs [25], and expanded to analyze 145 PCB congeners (Table 1 in Supplementary Content). 13 C 12 -PCBs 28, 123, 169 and 170 were used as internal standards for the quantitation of PCBs.…”

“…The total PCN levels (ΣPCNs) were reported as the sum of the concentrations of 37 individual congeners in Halowax 1014, in which PCN congener compositions were referred to in the study by Harner and Bidleman [27]. The total PBDE levels (ΣPBDEs) were reported as the sum of 27 congeners [25]. Percentage contribution of PCBs, PCNs and PBDEs congeners and homologues were calculated by dividing concentrations of individual congeners and homologues by ΣPCBs, ΣPCNs and ΣPBDEs, respectively.…”

“…ΣPCBs included 145 congeners [26]; ΣOCPs include ΣHCH, HCB, heptachlor and ΣDDTs; ΣDDTs is the total concentration of o,p' -DDE, p,p' -DDE, o,p' -DDD; p,p' -DDD; o,p' -DDT, and p,p' -DDT; ΣPBDEs is the total concentration of 27 congeners [25]; ΣHCH is the total concentration of α, β, γ, and δ-HCH isomers; ΣPCNs is the sum of the concentrations of individual congeners identified in Halowax 1014 [27]. The ratios in Figure 1 were calculated by averaging the ratios of the two-compared tissues of the 6-paired maternal and fetal seals rather than by using the data in Table 2.…”

“…ΣPCBs is the sum of the concentrations of 145 PCB congeners [26]; ΣPBDEs is the sum of the concentrations of 27 congeners [25]; ΣPCNs is the sum of the concentrations of 37 congeners identified in Halowax 1014 [27]. …”