PARENT SESSION

PH09 Fluorinated Chemicals
Exhibit Hall
8:00 AM - Thursday, 13 November 2003

(PH091) LC-MS/MS of Perfluoroalkylethanoic acids in fish from Lake Ontario.

Tomy, G¹, Halldorson, T¹, Whittle, M², Keir, M², Chittim, B³, Arsenault, G³, ¹ Department of Fisheries and Oceans, Winnipeg, Manitoba, Canada² Department of Fisheries and Oceans, Burlington, Ontario, Canada³ Wellington Laboratories Inc., Guelph, Ontario, Canada

ABSTRACT- Perfluoroalkyl ethanol compounds having the general formula C_nF_2n+1CH₂CH₂OH (n = 6, 8, 10, 12 or 14), have been shown to undergo oxidization to their corresponding carboxylic acids (C_nF_2n+1CH₂COOH) by microorganisms. The intent of the present study was to screen fish from Lake Ontario for perfluoroalkylethanoic acids (PFAEAs). Because no authentic standards of PFAEA exist, tentative assignment of PFAEAs in lake trout was based on the known fragmentation behaviour of similar fluorinated carboxylic acids under LC/MS/MS negative ESI conditions. For example, the ESI mass spectrum of perfluoropropyl propanoic acid (PFPPA, CF₃(CF₂)₂(CH₂)₂COOH), displayed peaks at m/z 241 corresponding to [M-H]^-, m/z 177 ([M-COOH-HF]^-) and peaks at m/z 157, 137 and 117 corresponding to successive losses of the neutral HF molecule. The loss of 4 HF atoms is consistent with the structure of PFPPA. Similarly, perfluorooctanoic acid (PFOA, C₇F₁₅COOH), which has no hydrogen atoms does not show a loss of HF, instead there is a peak at m/z 169 corresponding to C₃F₇^-. Based on the MS fragmentation patterns of these analogous compounds, fish were screened for four PFAEAs (n = 6, 8, 10 and 12). The first MRM transition examined was the [M-H]^- to m/z 169 [C₃F₇^-]. The results from this experiment, suggest that both the C6 and C8-PFAEAs are present in lake trout. The second MRM transition examined was the [M-H]^- to [M-COOH-2HF]^-; the results suggest that in addition to C6 and C8, C10-PFAEA is also present. If the acids being detecting are in fact ethanoic acids, then a loss of 3 HF molecules from the parent anion should not be observed. When examined, no such transitions were found, strongly suggesting that the acids detected were PFAEAs. Authentic standards of PFAEA are currently being synthesized, and will be used to confirm these preliminary results and quantify the PFAEAs detected.

Key words: Perfluoroalkyl ethanols, Perfluoroalkyl ethanoic acids , telomer alcohols, biotransformation