The sampling and identification of components in volatile organic mixtures

Public awareness of the toxic effects of some volatile organic compounds present in the working and home environment has created a requirement for the accurate measurement of the concentration of these substances. Similar techniques may be used for the examination of the volatile components of plant material and assist in determining the optimum economic time for harvesting, and also provide useful information in the areas of plant-insect interaction. This thesis examines some of the sampling and analytical aspects for the determination of trace volatile organic compounds present in air. A brief critical review of the literature is presented describing concentration and trapping techniques, headspace collection, separation and analytical techniques, detection and measurement of the separated components and the sources of error in trace volatile analysis. The development of an experimental sampling system for volatile organic compounds in air, based on trials conducted with activated carbon and a porous polymer is presented. Two methods of sample desorption are described and the development of sampling equipment based on Tenax GC, thermal elution with secondary trapping and flash injection into the inlet of a gas chromatograph is described. An investigation was conducted into the nature and origin of an unpleasant lachrimatory component emanating from an industrial furnace, and a number of trapping and separation techniques were used to determine the nature of the irritant. The experimental methods used are described, and conclusions are drawn concerning the suitability of the various techniques for trace organic volatile sampling. The steam volatile components of the oil of two Tasmanian native plants, Drimys lanceolata and Prostanthera lasianthos are examined using gas chromatography retention criteria on two columns and mass spectral information. A comparison of the volatile components of Boronia megastigma in the flowers, concrete, and.concrete headspace is described and the application of the technique to the determination of the optimum time for harvesting, is outlined. Changes in the volatile components produced upon injury of Pinus radiata are examined using headspace traps above and below the injury and comparisons are made of the volatile components present in the bark.