This project was the very beginning of research into the chemistry of eastern Australian banksia flowers. Using dynamic headspace sampling (DHS) analysis, differences in volatile components, consistent with detection of differences in odour, were detected among three different species and one commercial cultivar. Infraspecific variation was also observed between two known subspecies of Banksia ericifolia and between differently coloured forms of Banksia spinulosa var. collina. The cultivar, Banksia 'Giant Candles', was shown to have some of the chemical components of each of its supposed ancestors. The absence of known wound-response chemicals indicated that this DHS method was successful in leaving the inflorescences undamaged throughout the sampling procedure. The Likens-Nickerson modification of classical hydrodistillation methods was useful. The static headspace method (SHS) was easily automated and was shown to be chemically robust and sufficiently sensitive to detect volatile compounds from only a few flowers. The milder DHS method, which minimised mechanical and heat damage to the plant tissue, produced a different set of results. From the results of this project, a suite of volatile compounds has been proposed that may be useful in future behavioural studies to help determine whether animals are attracted to components of banksia odours. These candidates include some compounds that have been reported in animal secretions, wound-response chemicals that may be produced by the plant to aid its communication with other organisms, and a compound (suggested to be sulfanylmethyl acetate) not previously reported from natural sources. The mildest of the three analytical methods used, dynamic headspace sampling, was shown to be suitable for the potential chemotaxonomic evaluation of some members of the Banksia genus. / Doctor of Philosophy (PhD)

The global nitrogen cycle has been disrupted by large anthropogenic inputs of reactive nitrogen to the environment. Excess nitrogen underlies environmental problems such as eutrophication, and can negatively affect human health. Managing the natural microbial process of denitrification is advocated as a promising avenue to reduce excess nitrogen, and denitrifying bioreactors (DNBRs) are an emerging technology harnessing this biochemical process. Previous DNBR research has established successful nitrate removal, whereas this study examines the potential to expand DNBR functionality to address excess phosphorus and mitigate the production of nitrous oxide, a potent greenhouse gas. Results from a laboratory experiment supported the hypothesis that the addition of biochar, a charcoal-like soil amendment and novel organic carbon source in DNBR research, would increase nitrate and phosphorus removal as well as decrease the accumulation of nitrous oxide, an intermediate product of microbial denitrification. In order more closely examine the ratio of the products nitrous oxide and inert dinitrogen, development of a novel analytical method to quantify dissolved gases in environmental water samples using gas chromatography mass spectrometry was undertaken. Although static headspace analysis is a common technique for quantifying dissolved volatiles, the variation in sample preparation has recently been revealed to affect the determination of dissolved concentrations of permanent gases and convolute comparison between studies. This work demonstrates the viability of internal calibration with gaseous standard addition to make dissolved gas analysis more robust to variable sample processing and to correct for matrix effects on gas partitioning that may occur in environmental samples. / Master of Science

L’objectif de cette thèse était de réaliser des désodorisants, obtenus à partir de différentes essences naturelles. Ceux-ci doivent être efficaces dans l’amélioration du microclimat des atmosphères de travail. Une étude fondamentale sur l'optimisation de l'extraction des essences naturelles et l'identification des composants de ces essences a été réalisée par GC/MS. Nous avons étudié également les processus de reconnaissance moléculaire entre les composants majoritaires de ces essences et des CDs natives ou modifiées. La stabilité de ces complexes a été mesurée par trois méthodes différentes : l’headspace statique, la spectrophotométrie UV-visible et la microcalorimétrie de titration isotherme. La réalisation d’adsorbants à base de cyclodextrines a été effectuée en utilisant des polymères de cyclodextrine synthétisés à partir de l’épichlorhydrine ainsi que des matériaux hybrides de type CM-β-CD/LDH. L’efficacité des désodorisants obtenus a été évaluée en mesurant la durée de libération des composés odorants. / The objective of this thesis was to develop air fresheners from various natural essences. Those must be efficient in the improvement of working atmosphere microclimate. A fundamental study on the optimization of extraction of natural essences andidentification of components of these essences was performed by GC/MS. We have also studied the process of molecular recognition between the major components of these essences and native or modified CDs. The stability of these complexes was measured by three different methods: static headspace, UV-visible spectrophotometry and isothermal titration microcalorimetry.The realization of adsorbents supports based on cyclodextrins was carried out by using cyclodextrin polymers synthesized from epichlorohydrin and hybrid materials of CM-β-CD/LDH type. The efficiency of air fresheners was evaluated by measuring the release time of odorous compounds.