The Experts below are selected from a list of 1935 Experts worldwide ranked by ideXlab platform
Pingan Peng - One of the best experts on this subject based on the ideXlab platform.
-
compound specific stable carbon isotope analysis of Hexabromocyclododecane diastereoisomers using gas chromatography isotope ratio mass spectrometry
Rapid Communications in Mass Spectrometry, 2019Co-Authors: Gen Cheng, Shutao Gao, Yang Gao, Pingan PengAbstract:RATIONALE Compound-specific stable isotope analysis (CSIA) is a powerful tool for the source apportionment and characterization of environmental transformation processes, especially for new emerging contaminants. In this study, we have developed an effective method for determination of the stable carbon isotope ratios of Hexabromocyclododecane diastereoisomers. METHODS Three diastereoisomers of Hexabromocyclododecane (HBCD), α-, β-, and γ-HBCD, were separated on a preparative high-performance liquid chromatography (HPLC) system. Their carbon isotope ratios were determined using gas chromatography/isotope ratio mass spectrometry (GC/IRMS), and compared with data obtained by elemental analyzer/isotope ratio mass spectrometry (EA/IRMS). RESULTS α-, β-, and γ-HBCD were well separated by the preparative HPLC system. Method validation results indicated excellent precision and reproducibility. For a series of injection volumes (0.5 to 3 μL), the average carbon isotope ratios for α-HBCD, β-HBCD, and γ-HBCD were -26.42‰, -26.88‰, and -26.43‰, respectively, and their deviations from those of the HBCD standard (-26.52‰) were all lower than the analytical uncertainty of 0.5‰. Relative standard deviations of intra-day and inter-day injections of HBCD were in the ranges 0.35-0.64% and 0.37-0.76%, respectively. Comparison with EA/IRMS further verified the accuracy of the HBCD stable carbon isotope ratio measured by GC/IRMS. CONCLUSIONS This work offers a novel approach to separate and concentrate the three major isomers of HBCD and to determine their stable carbon isotope ratios. This permits analysis of their carbon isotope ratios in environmental samples in order to elucidate the sources and abiotic or biological transformation processes of HBCD in the environment.
Gen Cheng - One of the best experts on this subject based on the ideXlab platform.
-
compound specific stable carbon isotope analysis of Hexabromocyclododecane diastereoisomers using gas chromatography isotope ratio mass spectrometry
Rapid Communications in Mass Spectrometry, 2019Co-Authors: Gen Cheng, Shutao Gao, Yang Gao, Pingan PengAbstract:RATIONALE Compound-specific stable isotope analysis (CSIA) is a powerful tool for the source apportionment and characterization of environmental transformation processes, especially for new emerging contaminants. In this study, we have developed an effective method for determination of the stable carbon isotope ratios of Hexabromocyclododecane diastereoisomers. METHODS Three diastereoisomers of Hexabromocyclododecane (HBCD), α-, β-, and γ-HBCD, were separated on a preparative high-performance liquid chromatography (HPLC) system. Their carbon isotope ratios were determined using gas chromatography/isotope ratio mass spectrometry (GC/IRMS), and compared with data obtained by elemental analyzer/isotope ratio mass spectrometry (EA/IRMS). RESULTS α-, β-, and γ-HBCD were well separated by the preparative HPLC system. Method validation results indicated excellent precision and reproducibility. For a series of injection volumes (0.5 to 3 μL), the average carbon isotope ratios for α-HBCD, β-HBCD, and γ-HBCD were -26.42‰, -26.88‰, and -26.43‰, respectively, and their deviations from those of the HBCD standard (-26.52‰) were all lower than the analytical uncertainty of 0.5‰. Relative standard deviations of intra-day and inter-day injections of HBCD were in the ranges 0.35-0.64% and 0.37-0.76%, respectively. Comparison with EA/IRMS further verified the accuracy of the HBCD stable carbon isotope ratio measured by GC/IRMS. CONCLUSIONS This work offers a novel approach to separate and concentrate the three major isomers of HBCD and to determine their stable carbon isotope ratios. This permits analysis of their carbon isotope ratios in environmental samples in order to elucidate the sources and abiotic or biological transformation processes of HBCD in the environment.
Yang Gao - One of the best experts on this subject based on the ideXlab platform.
-
compound specific stable carbon isotope analysis of Hexabromocyclododecane diastereoisomers using gas chromatography isotope ratio mass spectrometry
Rapid Communications in Mass Spectrometry, 2019Co-Authors: Gen Cheng, Shutao Gao, Yang Gao, Pingan PengAbstract:RATIONALE Compound-specific stable isotope analysis (CSIA) is a powerful tool for the source apportionment and characterization of environmental transformation processes, especially for new emerging contaminants. In this study, we have developed an effective method for determination of the stable carbon isotope ratios of Hexabromocyclododecane diastereoisomers. METHODS Three diastereoisomers of Hexabromocyclododecane (HBCD), α-, β-, and γ-HBCD, were separated on a preparative high-performance liquid chromatography (HPLC) system. Their carbon isotope ratios were determined using gas chromatography/isotope ratio mass spectrometry (GC/IRMS), and compared with data obtained by elemental analyzer/isotope ratio mass spectrometry (EA/IRMS). RESULTS α-, β-, and γ-HBCD were well separated by the preparative HPLC system. Method validation results indicated excellent precision and reproducibility. For a series of injection volumes (0.5 to 3 μL), the average carbon isotope ratios for α-HBCD, β-HBCD, and γ-HBCD were -26.42‰, -26.88‰, and -26.43‰, respectively, and their deviations from those of the HBCD standard (-26.52‰) were all lower than the analytical uncertainty of 0.5‰. Relative standard deviations of intra-day and inter-day injections of HBCD were in the ranges 0.35-0.64% and 0.37-0.76%, respectively. Comparison with EA/IRMS further verified the accuracy of the HBCD stable carbon isotope ratio measured by GC/IRMS. CONCLUSIONS This work offers a novel approach to separate and concentrate the three major isomers of HBCD and to determine their stable carbon isotope ratios. This permits analysis of their carbon isotope ratios in environmental samples in order to elucidate the sources and abiotic or biological transformation processes of HBCD in the environment.
Shutao Gao - One of the best experts on this subject based on the ideXlab platform.
-
compound specific stable carbon isotope analysis of Hexabromocyclododecane diastereoisomers using gas chromatography isotope ratio mass spectrometry
Rapid Communications in Mass Spectrometry, 2019Co-Authors: Gen Cheng, Shutao Gao, Yang Gao, Pingan PengAbstract:RATIONALE Compound-specific stable isotope analysis (CSIA) is a powerful tool for the source apportionment and characterization of environmental transformation processes, especially for new emerging contaminants. In this study, we have developed an effective method for determination of the stable carbon isotope ratios of Hexabromocyclododecane diastereoisomers. METHODS Three diastereoisomers of Hexabromocyclododecane (HBCD), α-, β-, and γ-HBCD, were separated on a preparative high-performance liquid chromatography (HPLC) system. Their carbon isotope ratios were determined using gas chromatography/isotope ratio mass spectrometry (GC/IRMS), and compared with data obtained by elemental analyzer/isotope ratio mass spectrometry (EA/IRMS). RESULTS α-, β-, and γ-HBCD were well separated by the preparative HPLC system. Method validation results indicated excellent precision and reproducibility. For a series of injection volumes (0.5 to 3 μL), the average carbon isotope ratios for α-HBCD, β-HBCD, and γ-HBCD were -26.42‰, -26.88‰, and -26.43‰, respectively, and their deviations from those of the HBCD standard (-26.52‰) were all lower than the analytical uncertainty of 0.5‰. Relative standard deviations of intra-day and inter-day injections of HBCD were in the ranges 0.35-0.64% and 0.37-0.76%, respectively. Comparison with EA/IRMS further verified the accuracy of the HBCD stable carbon isotope ratio measured by GC/IRMS. CONCLUSIONS This work offers a novel approach to separate and concentrate the three major isomers of HBCD and to determine their stable carbon isotope ratios. This permits analysis of their carbon isotope ratios in environmental samples in order to elucidate the sources and abiotic or biological transformation processes of HBCD in the environment.
Adrian Covaci - One of the best experts on this subject based on the ideXlab platform.
-
flame retardant chemicals in college dormitories flammability standards influence dust concentrations
Environmental Science & Technology, 2017Co-Authors: Robin E Dodson, Adrian Covaci, Kathryn M Rodgers, Gale B Carey, Jose Guillermo Cedeno Laurent, Giulia Poma, Govindan Malarvannan, John D Spengler, Ruthann A Rudel, Joseph G AllenAbstract:Furniture flammability standards are typically met with chemical flame retardants (FRs). FRs can migrate out of products into dust and are linked to cancer, neurological impairment, and endocrine disruption. We collected 95 dust samples from dormitory common areas and student rooms on two U.S. college campuses adhering to two different furniture flammability standards: Technical Bulletin 117 (TB117) and Technical Bulletin 133 (TB133). Because TB133 requires furniture to withstand a much-more-demanding test flame than TB117, we hypothesized that spaces with TB133 furniture would have higher levels of FRs in dust. We found all 47 targeted FRs, including 12 polybrominated diphenyl ether (PBDE) congeners, 19 other brominated FRs, 11 phosphorus FRs (PFRs), 2 Dechlorane-Plus (DP) isomers, and 3 Hexabromocyclododecane (HBCDD) isomers in the 95 dust samples. We measured the highest reported U.S. concentrations for a number of FRs, including BDE 209 (up to 990 000 ng/g), which may be used to meet the TB133 standar...
-
occurrence of alternative flame retardants in indoor dust from new zealand indoor sources and human exposure assessment
Chemosphere, 2012Co-Authors: Nadeem Ali, Stuart Harrad, Hugo Neels, Alin C Dirtu, Nele Van Den Eede, Emma Goosey, Andrea T Mannetje, Jonathan Coakley, Jeroen Douwes, Adrian CovaciAbstract:Abstract Due to worldwide restrictions on polybrominated diphenyl ethers (PBDEs), the demand for alternative flame retardants (AFRs), such as organophosphate flame retardants (OPFRs), novel brominated FRs (NBFRs) and Hexabromocyclododecanes (HBCDs), has recently increased. Little is known about human exposure to NBFRs and OPFRs and that their levels in dust have been scarcely evaluated worldwide. To increase the knowledge regarding these chemicals, we measured concentrations of five major NBFRs, ten OPFRs and three HBCD isomers in indoor dust from New Zealand homes. Dust samples were taken from living room floors (n = 34) and from mattresses of the same houses (n = 16). Concentrations (ng g−1) of NBFRs were: 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) (
-
Hexabromocyclododecane current understanding of chemistry environmental fate and toxicology and implications for global management
Environmental Science & Technology, 2011Co-Authors: Christopher H Marvin, Gregg T Tomy, James M Armitage, Jon A Arnot, Lynn S Mccarty, Adrian Covaci, Vince P PalaceAbstract:Hexabromocyclododecane (HBCD) is a globally produced brominated flame retardant (BFR) used primarily as an additive FR in polystyrene and textile products and has been the subject of intensified research, monitoring and regulatory interest over the past decade. HBCD is currently being evaluated under the Stockholm Convention on Persistent Organic Pollutants. HBCD is hydrophobic (i.e., has low water solubility) and thus partitions to organic phases in the aquatic environment (e.g., lipids, suspended solids). It is ubiquitous in the global environment with monitoring data generally exhibiting the expected relationship between proximity to known sources and levels; however, temporal trends are not consistent. Estimated degradation half-lives, together with data in abiotic compartments and long-range transport potential indicate HBCD may be sufficiently persistent and distributed to be of global concern. The detection of HBCD in biota in the Arctic and in source regions and available bioaccumulation data also...
-
estimation of daily intake of organohalogenated contaminants from food consumption and indoor dust ingestion in romania
Environmental Science & Technology, 2010Co-Authors: Alin C Dirtu, Adrian CovaciAbstract:We estimated human exposure to organohalogenated contaminants (OHCs), including organochlorine pesticides (OCPs), such as hexachlorocyclohexanes (HCHs), DDT and metabolites, hexachlorobenzene, and chlordanes, but also polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and Hexabromocyclododecane (HBCD), through food consumption (mainly food of animal origin) and indoor dust ingestion in Romania. A total of 71 food samples (meat, diary products, vegetable cooking oil, and eggs from urban supermarkets and rural areas) and 18 indoor dust samples were collected from Iasi, Eastern Romania. HCHs and DDTs were the most prevalent OCPs in both food and dust samples. Higher levels of OCPs were measured in food samples collected from rural areas compared to those from urban supermarkets, except milk-based products for which no significant differences could be recorded. However, levels of contamination with HCHs in milk-based products were occasionally higher than current European maximum residu...
-
exposure to Hexabromocyclododecanes hbcds via dust ingestion but not diet correlates with concentrations in human serum preliminary results
Environmental Health Perspectives, 2009Co-Authors: Laurence Roosens, Stuart Harrad, Mohamed Abouelwafa Abdallah, Hugo Neels, Adrian CovaciAbstract:Background Hexabromocyclododecane (HBCD) is a high-production-volume chemical used as flame retardant in polystyrene insulation and textiles. Because it is not chemically bound to the polymer, HBCD can migrate into the environment, contaminating indoor dust and foodstuff.