NEW WAYS FOR THE ANALYTICAL CHARACTERIZATION OF HIGH-PURITY MATERIALS

In the analysis of high-purity materials one has always to fall back on multi-stage combined procedures, easy to calibrate, consisting of decomposition, preconcentration, and determination steps, if instrumental direct procedures (e.g. activation analysis, solid state mass spectrometry, optical emission spectrometry) are insufficiently sensitive or too unreliable. In the first part of this survey general experiences are reported of how such procedures can be optimally applied also to the ng/g-range. In the second part it is shown by means of four examples how to solve special problems: The examples 1 and 2 deal with the reliable determination of nitrogen and phosphorus in high-purity niobium. Example 3 refers to the spectrochemical detection of metallic impurities (e.g. Bi, Fe, Co, Zn) in high-purity metals after electrolytical preconcentration in a hydrodynamic system. In the 4th example a surface-analytical method, easy to calibrate, is presented which allows the depletion of thin-surface layers (≥10 nm) by anodic dissolution (electrolytic polishing). The element contents are then determined with high precision in the electrolyte. The capability of this method can be proved by measurement of the diffusion profiles of manganese and zinc in copper. © 1979 Springer-Verlag.