Recent problems and limitations in the analytical characterization of high-purity material.

The trend toward increasingly pure metals and semiconductor materials makes increasing demands upon their analytical characterization. The limits of direct methods of analysis (optical spectroscopy, mass spectroscopy, and activation analysis) can already be observed. In many cases, therefore. the contaminating elements have to be enriched before their determination. or they have to be separated from the matrix. These additional procedures increase the systematic possibilities of error (blank value, effects of adsorption, volatilization, etc.). General methods are described for their extensive elimination, especially during the decomposition and enrichment procedures. When these procedures are closely coupled with suitable detector systems, numerous elements (Be, B, C, N, O, Si, P, S, Se, Te, As, Sb and others) can still be determined very accurately in ng and pg amounts in the most diversified matrices.