Hydroxyalkylnitrate (Nitrooxyalkanole) als Spurenstoffe in belasteter und unbelasteter Atmosphäre

Abstract

Hydroxyl alkyl nitrates are the central topic in this work. Vicinal hydroxy alkyl nitrates are suspected to form from unsaturated hydrocarbons, mainly emitted by motor traffic. In order to investigate the presence of compounds in the atmosphere, well defined reference standards are required. By combining optimised synthesis routes with an improved HPLC clean-up procedure, 40 vicinal hydroxyl alkyl nitrates have been successfully isolated and clearly identified. The ECNI-mass spectra from the synthesised and purified hydroxyl alkyl nitrate were evaluated and a detailed analysis of fragment patterns was performed. This was then utilised to identify compounds in complex matrices such as an air sample, where no reference standards are available. Simulated pollution patterns, generated by chemical reaction of fuel, have been analysed and compared to pollution patterns measured in air masses, sampled at the island of Madeira/Portugal and at the University of Ulm/Germany. A clear connectivity between the entry of precursor molecules by motor traffic and the formation of hydroxy alkyl nitrates can be shown. It can be concluded after detailed analysis of air masses that hydroxyl alkyl nitrates play a significant role in the chemical reaction net of the atmosphere. Furthermore, the synthesis of other classes of organic nitrates (mono and multifunctional alkyl nitrates) enabled the optimisation of chromatographic separation conditions, for the analysis of organic nitrates. The retention characteristics of the synthesised reference compounds were utilised to improve the understanding of the physico-chemical behaviour of these complex molecules.