A critical study of some methods used to investigate atom formation processes in GFAAS

Proposed methods that yield information about mechanisms of atom formation, utilize the shapes of analytical signals that lie either under the rising or under the constant part of the temperature curve. We have evaluated both types of methods by use of a versatile data acquisition system, by which temperature and corresponding absorbance values were simultaneously sampled and stored. The stored data were subsequently used for calculations referring to arbitrary parts of the analytical signal, thus permitting accurate evaluations.Results obtained from “constant temperature methods” were found to be influenced by factors like sample amount, type of graphite surface and inner gas flow-rate. Meaningful results were only obtained for sample amounts larger than those used during normal working conditions.Results obtained from “rising temperature methods” were in rough agreement with each other. However, they all showed large standard deviations, indicating that several mechanisms are acting during atom formation. This makes it difficult to extract useful information from energy values obtained with these methods.