PARENT SESSION

IP10 Emerging Issues in Analytical Chemistry
B115 & B116
1:20 PM - 4:40 PM, Wednesday

(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