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IP10 Emerging Issues in Analytical Chemistry
(IP086) Refinements to the isomer-specific method for the analysis of hexabromocyclododecane (HBCD) by LC/MS/MS.
Tomy, G1, Halldorson, T1, Danell, R1, Law, K1, Arsenault, G2, Alaee, M3, Marvin, C3, 1 Department of Fisheries and Oceans, Winnipeg, Manitoba, Canada2 Wellington Laboratories Inc., Guelph, Ontario, Canada3 Environment Canada, Burlington, Ontario, Canada
ABSTRACT- Continued efforts to quantify HBCD in environmental matrices by our laboratory have highlighted some of the limitations of an isomer-specific LC/MS/MS method we developed previously. Our recent findings suggest that there is a pronounced suppression of the ion signal of native HBCD isomers in fish extracts - likely due to coeluting coextracted biogenic material in the matrix. In sediments we also observed differences in the extraction recoveries of spiked 13C-labelled internal standards likely due in part to differences in the hydrophobicity amongst the isomers. To circumvent these issues, newly synthesized labelled standards [deuterium (d18) and carbon (13C12)] have been incorporated at different steps into the analytical method. To monitor for extraction efficiencies and losses during clean-up, samples are spiked with three recovery internal standards (RIS: 13C12-, and -HBCD). Using all three 13C12-isomers as RIS and correcting the integrated ion signals of native HBCD isomers in samples with its corresponding 13C12 surrogate, differences in recoveries amongst the isomers are minimized. To overcome the matrix effect, three instrument performance internal standards (IPIS: d18-, and -HBCD) are added to the extract prior to injection. The ion signal of each IPIS is then used to correct both the signals of the corresponding recovery internal standards (13C12-isomers) and that of the native HBCD isomer. The use of these internal standards will ultimately improve our confidence in measuring environmental concentrations of HBCD in environmental samples.
Key words: LC/MS, hexabromocyclododecane, brominated flame retardant, analysis
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