Sökning: "ECD"

Visar resultat 1 - 5 av 22 avhandlingar innehållade ordet ECD.

  1. 1. Trace analysis of dioxins and dioxin-like PCBs using comprehensive two-dimensional gas chromatography with electron capture detection

    Författare :Conny Danielsson; Peter Haglund; Karin Wiberg; Jean-Marie Dimandja; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Comprehensive two-dimensional gas chromatography; GC × GC; µECD; PCDDs; PCDFs; dioxins; dioxin-like PCBs; Pressurized liquid extraction; PLE; PLE-C; food; feed; fly ash; soil; Environmental chemistry; Miljökemi;

    Sammanfattning : Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), two groups of struc-turally related chlorinated aromatic hydrocarbons, generally referred to as “dioxins” are of great concern due to their extreme toxicity and presence in all compartments of the environment. Since they occur at very low levels, their analysis is complex and challenging, and there is a need for cost-efficient, reliable and rapid analytical alternatives to the expensive methods in-volving use of gas chromatography high-resolution mass spectrometry (GC-HRMS). LÄS MER

  2. 2. Analysis of PCBs with special emphasis on comprehensive two-dimensional gas chromatography of atropisomers

    Författare :Mikael Harju; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Environmental chemistry; PCB; Atropisomers; Chiral; GC×GC; Enantiomeric barriers; Seal; polar; shape selective; Cyclodextrin; 2D; ECD; FID; TOF-MS; Comprehensive two-dimensional GC; Miljökemi; Environmental chemistry; Miljökemi; analytisk kemi; Analytical Chemistry;

    Sammanfattning : There are 209 PCB congeners, 136 of which have been found in technical PCB mixtures and hence may be found in the environment as a result of either intentional or unintentional release. The identification and quantification of the congeners are difficult due to analytical bias from coeluting PCBs and other persistent organic pollutants. LÄS MER

  3. 3. The Influence of Steel Sheet Surface-Topography on Friction in Stamping

    Författare :Anders Wihlborg; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Micro Plasto HydroDynamic Lubrication MPHDL ; EBT; ECD; EDT; WC index; SBT; surface topography; Micro Plasto HydroStatic Lubrication MPHSL ; tribology; steel sheets; Surface Indentation Test; bending under tension;

    Sammanfattning : Steel sheet is the prevalent material for car body panels. In the manufacturing of steel sheets a certain surface roughness is achieved from the ground or textured rolls used in the three final reduction steps. When manufacturing car body panels the sheets first are formed and then painted. LÄS MER

  4. 4. Dynamics of astaxanthin, tocopherol (Vitamin E) and thiamine (Vitamin B1) in the Baltic Sea ecosystem : Bottom-up effects in an aquatic food web

    Författare :Norbert Häubner; Pauli Snoeijs; Jon Ågren; Rhena Schumann; Markku Viitasalo; Uppsala universitet; []
    Nyckelord :Baltic Sea; carotenoids; astaxanthin; tocopherols; Vitamin E; thiamine; Vitamin B1; pelagic food web; eutrophication; M74; phytoplankton; zooplankton; sprat; Sprattus sprattus balticus; herring; Clupea harengus; salmon; Salmo salar; cod; Gadus morhua; High Performance Liquid Chromatography HPLC ; electrochemical detection ECD ;

    Sammanfattning : The thesis combines laboratory experiments and field expeditions to study production, transfer and consumption of non-enzymatic antioxidants and thiamine in an aquatic food web. In particular, I (1) documented spatial and seasonal variation of tocopherols and carotenoids in the Baltic Sea pelagic food web, and (2) examined the effects of abiotic and biotic factors on tocopherol, carotenoid and thiamine concentrations in phytoplankton, zooplankton and fish. LÄS MER

  5. 5. Characterization of Polypeptides by Tandem Mass Spectrometry Using Complementary Fragmentation Techniques

    Författare :Michael Lund Nielsen; Roman A. Zubarev; Per Andrén; Ole Nörregaard Jensen; Uppsala universitet; []
    Nyckelord :Analytical chemistry; Mass Spectrometry; Electron capture dissociation ECD ; Collision-activated dissociation CAD ; Proteomics; Post-translational modifications; De Novo sequencing; Bioinformatics; Analytisk kemi;

    Sammanfattning : In the growing field of proteomics identification of proteins by tandem mass spectrometry (MS/MS) is performed by matching experimental mass spectra against calculated spectra of all possible peptides in a protein database. One problem with this approach is the false-positive identifications. LÄS MER