title: Untargeted Identification of Organo-Bromine Compounds in Lake Sediments by Ultrahigh-Resolution Mass Spectrometry with the Data-Independent Precursor Isolation and Characteristic Fragment Method.
abstract: While previous studies have found that unknown natural and synthetic organo-bromine compounds (NSOBCs) contributed more than 99% of the total organic bromine (Br) in the environment, there was no efficient method for untargeted screening to identify NSOBCs in environmental matrixes. A novel untargeted method for identifying NSOBCs, based on ultrahigh-resolution mass spectrometry (UHRMS) with the Q Exactive instrument was developed. This method included a data-independent precursor isolation and characteristic fragment (DIPIC-Frag) procedure to identify NSOBCs. A total of 180 successive 5-m/z-wide windows were used to isolate precursor ions. This resulted in a sufficient dynamic range and specificity to identify peaks of Br fragment ions for analysis. A total of 2520 peaks of NSOBC compounds containing Br were observed in sediments from Lake Michigan, United States. A new chemometric strategy which combined chromatographic profiles, isotopic peaks, precursor isolation window information, and intensities was used to identify precursor ions and chemical formulas for detecting NSOBCs. Precursor ions for 2163 of the 2520 NSOBCs peaks (86%) were identified, and chemical formulas for 2071 NSOBCs peaks (82%) were determined. After exclusion of isotopic peaks, 1593 unique NSOBCs were identified and chemical formulas derived for each. Most of the compounds identified had not been reported previously and had intensities which were 100- to 1000-fold greater than the congeners of polybrominated diphenyl ethers (PBDEs). In extracts of sediments, these compounds exhibited variations in intensities (<10(3) to ∼10(8)), m/z values (170.9438-997.5217), retention times on a C18 column (1.0-29.3 min), and the number of Br atoms (1-8). Generally, compounds with greater m/z values had longer retention times and greater numbers of Br atoms. Three compounds were used in a proof-of-concept experiment to demonstrate that structures of some of the screened NSOBCs could be further predicted by combining searching of database libraries and high-resolution MS(2) spectra.
authors.affiliation: Toxicology Centre, University of Saskatchewan , 44 Campus Drive, Saskatoon, Saskatchewan Canada , S7N 5B3.
authors.forename: Hui
authors.initials: H
authors.lastname: Peng
authors.affiliation: Toxicology Centre, University of Saskatchewan , 44 Campus Drive, Saskatoon, Saskatchewan Canada , S7N 5B3.
authors.forename: Chunli
authors.initials: C
authors.lastname: Chen
authors.affiliation: Toxicology Centre, University of Saskatchewan , 44 Campus Drive, Saskatoon, Saskatchewan Canada , S7N 5B3.
authors.forename: David M V
authors.initials: DM
authors.lastname: Saunders
authors.affiliation: Toxicology Centre, University of Saskatchewan , 44 Campus Drive, Saskatoon, Saskatchewan Canada , S7N 5B3.
authors.forename: Jianxian
authors.initials: J
authors.lastname: Sun
authors.affiliation: School of Environment and Sustainability , 117 Science Place, Saskatoon, Saskatchewan Canada , S7N 5C8.
authors.forename: Song
authors.initials: S
authors.lastname: Tang
authors.affiliation: Toxicology Centre, University of Saskatchewan , 44 Campus Drive, Saskatoon, Saskatchewan Canada , S7N 5B3.
authors.forename: Garry
authors.initials: G
authors.lastname: Codling
authors.affiliation: Toxicology Centre, University of Saskatchewan , 44 Campus Drive, Saskatoon, Saskatchewan Canada , S7N 5B3.|School of Environment and Sustainability , 117 Science Place, Saskatoon, Saskatchewan Canada , S7N 5C8.
authors.forename: Markus
authors.initials: M
authors.lastname: Hecker
authors.affiliation: Toxicology Centre, University of Saskatchewan , 44 Campus Drive, Saskatoon, Saskatchewan Canada , S7N 5B3.
authors.forename: Steve
authors.initials: S
authors.lastname: Wiseman
authors.affiliation: Toxicology Centre, University of Saskatchewan , 44 Campus Drive, Saskatoon, Saskatchewan Canada , S7N 5B3.|School of Environment and Sustainability , 117 Science Place, Saskatoon, Saskatchewan Canada , S7N 5C8.
authors.forename: Paul D
authors.initials: PD
authors.lastname: Jones
authors.affiliation: School of Public Health, University of Illinois at Chicago , Chicago, Illinois 60612, United States.
authors.forename: An
authors.initials: A
authors.lastname: Li
authors.affiliation: Department of Civil and Materials Engineering (MC 246), University of Illinois at Chicago , 842 West Taylor Street, Chicago, Illinois 60607-7023, United States.
authors.forename: Karl J
authors.initials: KJ
authors.lastname: Rockne
authors.affiliation: Toxicology Centre, University of Saskatchewan , 44 Campus Drive, Saskatoon, Saskatchewan Canada , S7N 5B3.|Department of Veterinary Biomedical Sciences, University of Saskatchewan , Saskatoon, Saskatchewan Canada S7N 5B3.|Zoology Department, Center for Integrative Toxicology, Michigan State University , East Lansing, Michigan 48824 United States.|School of Biological Sciences, University of Hong Kong , Hong Kong Special Administrative Region, Peoples Republic of China.|State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University , Nanjing 210023, People's Republic of China.|Biology Department, Hong Kong Baptist University , Hong Kong, Special Administrative Region, China.
authors.forename: John P
authors.initials: JP
authors.lastname: Giesy
mesh_terms: D062126:Databases, Chemical; D019015:Geologic Sediments / Q000737:chemistry*; D006842:Hydrocarbons, Brominated / Q000032:analysis*; D060106:Lakes / Q000737:chemistry*; D013058:Mass Spectrometry / Q000379:methods*
chemical_list: D006842:Hydrocarbons, Brominated