@article {103, title = {Untargeted Screening and Distribution of Organo-Bromine Compounds in Sediments of Lake Michigan.}, journal = {Environ Sci Technol}, volume = {50}, year = {2016}, month = {2016 Jan 05}, pages = {321-30}, abstract = {

Previously unreported natural and synthetic organo-bromine compounds (NSOBCs) have been found to contribute more than 99\% of total organic bromine (TOB) in environmental matrices. We recently developed a novel untargeted method (data-independent precursor isolation and characteristic fragment, DIPIC-Frag) and identified \~{}2000 NSOBCs in two sediments from Lake Michigan. In this study, this method was used to investigate the distributions of these NSOBCs in 23 surficial samples and 24 segments of a sediment core from Lake Michigan. NSOBCs were detected in all 23 surficial samples and exhibited 10- to 100-fold variations in peak abundance among locations. The pattern of distributions of NSOBCs was correlated with depth of the water column (r(2) = 0.61, p \< 0.001). Hierarchical cluster analysis showed that sediments in close proximity exhibited similar profiles of NSOBCs. Distributions of NSOBCs in 24 segments of a sediment core dated from 1766 to 2008 were investigated, and samples from similar depths exhibited similar profiles of NSOBCs. NSOBCs were grouped into four clusters (soft-cluster analysis) with different temporal trends of abundances. 515 and 768 of the NSOBCs were grouped into cluster 1 and cluster 3 with increasing temporal trends, especially since 1950, indicating that abundances of these compounds might have been affected by human activities.

}, keywords = {Bromine Compounds, Environmental Monitoring, Geologic Sediments, Halogenated Diphenyl Ethers, Hydrocarbons, Brominated, Lakes, Michigan, Water Pollutants, Chemical}, issn = {1520-5851}, doi = {10.1021/acs.est.5b04709}, author = {Peng, Hui and Chen, Chunli and Cantin, Jenna and Saunders, David M V and Sun, Jianxian and Tang, Song and Codling, Garry and Hecker, Markus and Wiseman, Steve and Jones, Paul D and Li, An and Rockne, Karl J and Sturchio, Neil C and Giesy, John P} } @article {98, title = {Untargeted Screening and Distribution of Organo-Iodine Compounds in Sediments from Lake Michigan and the Arctic Ocean.}, journal = {Environ Sci Technol}, volume = {50}, year = {2016}, month = {2016 09 20}, pages = {10097-105}, abstract = {

The majority of halogenated organic compounds present in the environment remain unidentified. To address this data gap, we recently developed an untargeted method (data-independent precursor isolation and characteristic fragment; DIPIC-Frag) for identification of unknown organo-bromine compounds. In this study, the method was adapted to enable untargeted screening of natural and synthetic organo-iodine compounds (NSOICs) in sediments. A total of 4,238 NSOIC peaks were detected in sediments from Lake Michigan. Precursor ions and formulas were determined for 2,991 (71\%) of the NSOIC peaks. These compounds exhibited variations in abundances (\<10(3) to \~{}10(7)), m/z values (206.9304-996.9474), retention times (1.0-29.7 min), and number of iodine atoms (1-4). Hierarchical cluster analysis showed that sediments in closer proximity exhibited similar profiles of NSOICs. NSOICs were screened in 10 samples of sediment from the Arctic Ocean to compare the profiles of NSOICs between freshwater and marine sediments. A total of 3,168 NSOIC peaks were detected, and profiles of NSOICs in marine sediments were clearly distinct from Lake Michigan. The coexistence of brominated and iodinated analogues indicated that some NSOICs are of natural origin. Different ratios of abundances of iodinated compounds to brominated analogues were observed and proposed as a marker to distinguish sources of NSOICs.

}, keywords = {Geologic Sediments, Iodine Compounds, Lakes, Michigan, Oceans and Seas, Water Pollutants, Chemical}, issn = {1520-5851}, doi = {10.1021/acs.est.6b03221}, author = {Peng, Hui and Chen, Chunli and Cantin, Jenna and Saunders, David M V and Sun, Jianxian and Tang, Song and Codling, Garry and Hecker, Markus and Wiseman, Steve and Jones, Paul D and Li, An and Rockne, Karl J and Sturchio, Neil C and Cai, Minghong and Giesy, John P} } @article {105, 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.}, journal = {Anal Chem}, volume = {87}, year = {2015}, month = {2015 Oct 20}, pages = {10237-46}, 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.

}, keywords = {Databases, Chemical, Geologic Sediments, Hydrocarbons, Brominated, Lakes, Mass Spectrometry}, issn = {1520-6882}, doi = {10.1021/acs.analchem.5b01435}, author = {Peng, Hui and Chen, Chunli and Saunders, David M V and Sun, Jianxian and Tang, Song and Codling, Garry and Hecker, Markus and Wiseman, Steve and Jones, Paul D and Li, An and Rockne, Karl J and Giesy, John P} }