CONTAMINATION BY HEAVY-METALS IN REACTIVE PROCESS GASES

In recent years, heavy metal contaminants have become increasingly significant in almost all areas of application of high-purity gases. The analysis of these contaminants is still in the early stages and has proved inadequate, regarding the importance of the contaminations. The methods described are an attempt to address the problem but do not represent the final solution. For model system Fe in HCl three different analytical systems to analyse the heavy metal content of reactive gases were developed and described: limits of the applicability of the cheap and simple impinger-system could be revealed a first monitoring method to determine traces of metals in reactive gases could be realised by Continuous Flow Analysis. detection limits at about 2 ng/g for Fe in gaseous HCl and the possibility of monitoring became possible by the development of ICP/OES with direct introduction of reactive gases. Comprehensive research, particularly with regard to the specification of heavy metal contaminations, will be necessary before reliable analysis can be introduced into routine operation of process monitoring or quality control.