[en] The mass spectrometer for secondary ions, the ion-microprobe, constructed at the Research-Center of Seibersdorf has a high resolution (1 μm). It works with two double-focussing mass spectrometers which permit a dynamic sensitivity of more than 10⁹. The thesis concerns with the application of this apparatus in the qualitative analysis of the surface of solid samples, the correlation of the peaks with atomic or molecular ions and the determination of their concentration by revised ionization theories of Anderson et al and Schroeer. A peakswitcher developed in the course of the thesis is described. (C.R.)