Global ETD Search
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Showing 1 to 16 of 16 for “"Two-dimensional gas chromatography"”.
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Two-dimensional gas chromatography : a novel technique for iron low temperature Fischer-Tropsch selectivity studies
… technology and the development of comprehensive two-dimensional gas chromatography (GCxGC) it may now be possible to analyze the complex Fischer-Tropsch products in a relatively short time while delivering good separation of even minor compounds such as oxygenates and branched compounds. The aim …
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On-line screening of bioactive compounds and application of comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry for the analysis of birch bark
… methods. In this system, high-performance liquid chromatography separates complex mixtures, and a post-column biochemical assay determines the activity of the individual compounds present in the mixtures. At the same time, parallel chemical detection techniques (e.g., diode-array detection, mass …
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Quantification of pyrethroid and organophosphate metabolites in hair and urine samples of rural children from the Western Cape, South Africa using the two-dimensional gas chromatography-mass spectrometry
… and minimize exposure risks. However, existing chromatography monitoring systems encounter challenges such as sensitivity and matrix effects when quantifying these compounds in complex biological samples. This study evaluated a two-dimensional gas chromatography coupled with a time-of-flight …
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Development of a sampling system for the collection of exhaled breath condensates and its subsequent analysis using 2-dimensional gas chromatography
… are successfully collected and analyzed using gas chromatography - mass spectrometry (GC-MS) as well as two-dimensional gas chromatography (GCxGC). This provides analysis of volatile organic compounds as well as proteins and higher molecular weight components present in breath. This broader …
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Using passive samplers to assess bioavailability, toxicity, and reactivity of hydrophobic organic chemicals (HOCs)
… based on passive sampling and comprehensive two dimensional gas chromatography (GC × GC). Using GC × GC retention times, we show that lipid-water and samplerwater partition coefficients can be estimated within a factor of 2 and 3, respectively. The method was then applied to estimate body …
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Analysis of the volatile organic compounds produced by the decomposition of pig carcasses and human remains
… and were analyzed using thermal desorption gas chromatography mass spectrometry (TD-GC-MS). The difficulties associated with the non-target analysis of complex samples led to the further analysis of decomposition odour using a novel application of thermal desorption coupled to comprehensive …
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Characterising the immunometabolic profile of HIV/TB co-infection
… cytokine measurements, and an untargeted two-dimensional gas chromatography time-of-flight mass spectrometry approach was used for metabolomics analyses. There was no significant difference between the cytokine levels of the diseased groups when compared to each other or the controls, …
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Using passive samplers to assess bioavailability, toxicity, and reactivity of hydrophobic organic chemicals (HOCs)
… based on passive sampling and comprehensive two dimensional gas chromatography (GC x GC). Using GC x GC retention times, we show that lipid-water and samplerwater partition coefficients can be estimated within a factor of 2 and 3, respectively. The method was then applied to estimate body …
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Application of Polychlorinated Biphenyl Signatures for Environmental Fingerprinting
… biological matrices (blood and tissues). A two dimensional gas chromatography with time of flight mass spectrometry (GCxGC-ToFMS) method was designed and optimised to provide a congener specific method capable of identifying 200 out of the 209 PCBs, with detection limits in human serum in …
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Adding ammonia during Fischer-Tropsch Synthesis: Pathways to the formation of N-containing compounds
… = 0.2 bar) where NH₃ is co-fed with synthesis gas during FTS. The individual adsorptions of CO and NHₓ (with x = 3, 2, 1, 0) were compared to their coadsorbed states, by calculating the heat of mixing (ΔEmix) and the activation barriers (Eₐ) for CO dissociation in the presence and absence of …
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The effect of different sample preparatory protocols on the induction of the aryl hydrocarbon receptor (AhR) in the H4IIE–luc reporter gene bio–assay
… with a manual acid digestion, gel permeation chromatography (GPC) and Florisil fractionation clean-up procedure as well as the automated Total Rapid Prep™(TRP) system which makes use of a PLE combined with a multi-layer silica, alumina and carbon column clean-up procedure. To evaluate the …
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Biodegradation, water solubility and characterisation studies of unresolved complex mixtures (UCMs) of aromatic hydrocarbons
… dissolution of complex mixtures. Comprehensive two-dimensional gas chromatography-time of flight-mass spectrometry (GCxGC-ToF-MS) analysis was used to provide vastly increased separation power and characterisation of a water 'soluble' monoaromatic UCM. Over 1200 compounds were separated by the …
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Generation, Characterisation and Potential Health Effects of Tyre Wear Particles
… apportionment calculations. Using untargeted two-dimensional gas chromatography-mass spectrometry, the chemical composition of tyre rubber has been analysed for chemicals of potential environmental concern, aiding in hazard assessment. To aid in classification, chemicals have been assigned …