title: Identification of Novel Perfluoroalkyl Ether Carboxylic Acids (PFECAs) and Sulfonic Acids (PFESAs) in Natural Waters Using Accurate Mass Time-of-Flight Mass Spectrometry (TOFMS).
abstract: Recent scientific scrutiny and concerns over exposure, toxicity, and risk have led to international regulatory efforts resulting in the reduction or elimination of certain perfluorinated compounds from various products and waste streams. Some manufacturers have started producing shorter chain per- and polyfluorinated compounds to try to reduce the potential for bioaccumulation in humans and wildlife. Some of these new compounds contain central ether oxygens or other minor modifications of traditional perfluorinated structures. At present, there has been very limited information published on these "replacement chemistries" in the peer-reviewed literature. In this study we used a time-of-flight mass spectrometry detector (LC-ESI-TOFMS) to identify fluorinated compounds in natural waters collected from locations with historical perfluorinated compound contamination. Our workflow for discovery of chemicals included sequential sampling of surface water for identification of potential sources, nontargeted TOFMS analysis, molecular feature extraction (MFE) of samples, and evaluation of features unique to the sample with source inputs. Specifically, compounds were tentatively identified by (1) accurate mass determination of parent and/or related adducts and fragments from in-source collision-induced dissociation (CID), (2) in-depth evaluation of in-source adducts formed during analysis, and (3) confirmation with authentic standards when available. We observed groups of compounds in homologous series that differed by multiples of CF2 (m/z 49.9968) or CF2O (m/z 65.9917). Compounds in each series were chromatographically separated and had comparable fragments and adducts produced during analysis. We detected 12 novel perfluoroalkyl ether carboxylic and sulfonic acids in surface water in North Carolina, USA using this approach. A key piece of evidence was the discovery of accurate mass in-source n-mer formation (H(+) and Na(+)) differing by m/z 21.9819, corresponding to the mass difference between the protonated and sodiated dimers.
authors.affiliation: National Exposure Research Laboratory, U.S. Environmental Protection Agency , Research Triangle Park, North Carolina 27711, United States.
authors.forename: Mark
authors.initials: M
authors.lastname: Strynar
authors.affiliation: National Exposure Research Laboratory, U.S. Environmental Protection Agency , Research Triangle Park, North Carolina 27711, United States.|Oak Ridge Institute for Science and Education , Oak Ridge, Tennessee 37831 United States.
authors.forename: Sonia
authors.initials: S
authors.lastname: Dagnino
authors.affiliation: National Exposure Research Laboratory, U.S. Environmental Protection Agency , Research Triangle Park, North Carolina 27711, United States.|Oak Ridge Institute for Science and Education , Oak Ridge, Tennessee 37831 United States.
authors.forename: Rebecca
authors.initials: R
authors.lastname: McMahen
authors.affiliation: National Exposure Research Laboratory, U.S. Environmental Protection Agency , Research Triangle Park, North Carolina 27711, United States.|Oak Ridge Institute for Science and Education , Oak Ridge, Tennessee 37831 United States.
authors.forename: Shuang
authors.initials: S
authors.lastname: Liang
authors.affiliation: National Exposure Research Laboratory, U.S. Environmental Protection Agency , Research Triangle Park, North Carolina 27711, United States.
authors.forename: Andrew
authors.initials: A
authors.lastname: Lindstrom
authors.affiliation: National Exposure Research Laboratory, U.S. Environmental Protection Agency , Research Triangle Park, North Carolina 27711, United States.
authors.forename: Erik
authors.initials: E
authors.lastname: Andersen
authors.affiliation: National Caucus and Center on Black Aged, Inc. , Durham, North Carolina 27713, United States.
authors.forename: Larry
authors.initials: L
authors.lastname: McMillan
authors.affiliation: Center for Environmental Mass Spectrometry, University of Colorado Boulder , Boulder, Colorado 80309, United States.
authors.forename: Michael
authors.initials: M
authors.lastname: Thurman
authors.affiliation: Center for Environmental Mass Spectrometry, University of Colorado Boulder , Boulder, Colorado 80309, United States.
authors.forename: Imma
authors.initials: I
authors.lastname: Ferrer
authors.affiliation: Agilent Technologies Inc. , Wilmington, Delaware 19808, United States.
authors.forename: Carol
authors.initials: C
authors.lastname: Ball
mesh_terms: D002264:Carboxylic Acids / Q000032:analysis* / Q000737:chemistry; D005591:Chemical Fractionation; D004987:Ethers / Q000032:analysis / Q000737:chemistry; D005466:Fluorocarbons / Q000032:analysis* / Q000737:chemistry; D006801:Humans; D009657:North Carolina; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013451:Sulfonic Acids / Q000032:analysis / Q000737:chemistry; D014867:Water / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry
chemical_list: D002264:Carboxylic Acids; D004987:Ethers; D005466:Fluorocarbons; D013451:Sulfonic Acids; D014874:Water Pollutants, Chemical; D014867:Water