Optimisation and application of different electron probe X-ray microanalysis approaches for the chemical characterisation of individual environmental particles

The study of atmospheric aerosols has recently become very important for two major reasons: the small particle size fraction has a very important influence on human health, and it affects the global climate. Characterization of individual microscopic particles generally permits more information to be obtained than is feasible with bulk analysis. As a result recognition of pollution sources and processes becomes simplified and facilitated. The characterisation of single environmental particles using micro-analytical techniques plays an important role in the environmental science.; In the framework of this PhD, particular attention was paid to the application of electron probe microanalysis (EPMA) to the analysis of single environmental particles.; Apart from the thin-window EPMA approaches, there are also other alternative EPMA methods. For samples containing large numbers of biogenic and organic particles impregnation with heavy metals can be used. The “spot-test” or microchemical transformation is another analytical procedure based on micro-chemical reactions. Their use in optical microscopy is described, while their application to common atmospheric aerosol anions such as sulphate, chloride, or nitrate is also addressed.; Using thin-window EPMA, the low-Z element information is obtained to better accounted for the overall chemical composition. In this way the classification of individual particles can be at least semi-quantitatively assessed. However, one of the most important problems of EPMA remains beam damage, which causes geometrical and morphological structures to be changed during analysis. These artifacts cannot be accounted for in quantitative concentration calculations. It should also be noted that knowledge about the particle concentrations plays a very significant role in the study of environmental pollution. The use of a liquid-nitrogen-cooled sample stage during the automated analysis of the atmospheric aerosol particles results in a spectacular protection against the beam damage effect. It seems that the beam damage depends not only on the composition of the particles, but also the diameter of the particles and their shape. Moreover, the collection substrate for atmospheric particles play an important role during the beam damage process.; In the framework of these PhD investigations, some examples of the application of quantitative thin-window EPMA in environmental research are presented. The results from the analysis of the individual atmospheric particles collected in the Amazon Basin, South Africa and Balaton Lake in Hungary are discussed in detail. Since the development and the optimisation of this new method are still in progress, the interpretation of the results and quantification should be done with caution. The comparison of the quantitative results from thin-window EPMA with those obtained from the conventional EPMA is also presented in detail. (Abstract shortened by UMI.)...