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Method development for non-routine compound specific stable isotope analysis (CSIA) of light elements
Multi-dimensional compound specific stable isotope analysis (CSIA) is a promising new analytical approach wherein changes in isotope ratios are measured across multiple elements within a given compound, shedding light on reaction mechanisms and allowing for the identification and characterisation of the origin, distribution, conversion, and degradation of organic chemicals. Thus far, routine methods are available for measurements of carbon and hydrogen isotopes; however, in order to fully exploit the potential of multi-dimensional CSIA, new approaches are needed for halogen, oxygen, and hydrogen stable isotope analysis in heteroatom-bearing compounds. In order to facilitate such an expansion, the work described in this thesis was aimed at the development of methods for CSIA for rarely-analysed chlorine and oxygen stable isotopes, as well as to improve hydrogen stable isotope analysis for halogenated compounds, which were previously inaccessible. The presented approaches used high temperature conversion (HTC, >1200 °C) to generate HCl, CO, and H2 analyte gas from organic compounds online after gas chromatographic (GC) separation. For respective stable isotope ratio determination of those analyte gases, the GC-HTC interface was interlinked with a gas analyser (qMS) and later an isotope ratio mass spectrometer (IRMS). For conversion characterisation an organic mass spectrometer (IonTrap MS) was used in parallel at the end of the tested reactors. Chlorine stable isotope analysis using GC-HTC-IRMS was achieved for a set of chlorinated compounds. Hydrogen stable isotope analysis of heteroatom-bearing (Cl, N, S) substances was improved fundamentally by providing chromium powder in the reactor. The developed novel GC-Cr/HTC-IRMS method was successfully validated and implemented for hydrogen CSIA. Investigations of the commercially available reactor for oxygen GC-HTC-IRMS showed undesired by-products and HTC processes which inhibited reproducible and accurate CSIA of volatile organic compounds. For future method development and to identify and quantify interfering by-products in GC-HTC-IRMS in general, an evaluation strategy is proposed. In summary, GC-HTC-IRMS approaches were investigated and successfully applied to extend the existing repertoire of non-routine CSIA methods for chlorine, hydrogen and oxygen stable isotopes.
Method development for non-routine compound specific stable isotope analysis (CSIA) of light elements
Multi-dimensional compound specific stable isotope analysis (CSIA) is a promising new analytical approach wherein changes in isotope ratios are measured across multiple elements within a given compound, shedding light on reaction mechanisms and allowing for the identification and characterisation of the origin, distribution, conversion, and degradation of organic chemicals. Thus far, routine methods are available for measurements of carbon and hydrogen isotopes; however, in order to fully exploit the potential of multi-dimensional CSIA, new approaches are needed for halogen, oxygen, and hydrogen stable isotope analysis in heteroatom-bearing compounds. In order to facilitate such an expansion, the work described in this thesis was aimed at the development of methods for CSIA for rarely-analysed chlorine and oxygen stable isotopes, as well as to improve hydrogen stable isotope analysis for halogenated compounds, which were previously inaccessible. The presented approaches used high temperature conversion (HTC, >1200 °C) to generate HCl, CO, and H2 analyte gas from organic compounds online after gas chromatographic (GC) separation. For respective stable isotope ratio determination of those analyte gases, the GC-HTC interface was interlinked with a gas analyser (qMS) and later an isotope ratio mass spectrometer (IRMS). For conversion characterisation an organic mass spectrometer (IonTrap MS) was used in parallel at the end of the tested reactors. Chlorine stable isotope analysis using GC-HTC-IRMS was achieved for a set of chlorinated compounds. Hydrogen stable isotope analysis of heteroatom-bearing (Cl, N, S) substances was improved fundamentally by providing chromium powder in the reactor. The developed novel GC-Cr/HTC-IRMS method was successfully validated and implemented for hydrogen CSIA. Investigations of the commercially available reactor for oxygen GC-HTC-IRMS showed undesired by-products and HTC processes which inhibited reproducible and accurate CSIA of volatile organic compounds. For future method development and to identify and quantify interfering by-products in GC-HTC-IRMS in general, an evaluation strategy is proposed. In summary, GC-HTC-IRMS approaches were investigated and successfully applied to extend the existing repertoire of non-routine CSIA methods for chlorine, hydrogen and oxygen stable isotopes.
Method development for non-routine compound specific stable isotope analysis (CSIA) of light elements
Hitzfeld, Kristina Lotte (author)
2016
Miscellaneous
Electronic Resource
English
gas chromatography high temperature conversion isotope ratio mass spectrometry (GC-HTC-IRMS) , Gas Chromatographie - Hochtemperaturumsetzung - Isotopen Verhältnis Massenspektrometrie (GC-HTC-IRMS) , komponentenspezifische stabile Isotopen Analytik (CSIA) , compound specific stable isotope analysis (CSIA) , stable isotopes (chlorine, hydrogen, oxygen) , stabile Isotope (Chlor, Wasserstoff, Sauerstoff) , Isotop , Massenspektrometrie
| UB Braunschweig | 2016
| TIBKAT | 2016
| UB Braunschweig | 2014
| TIBKAT | 2014