Qualitative X-Ray Analysis

The first stage in the analysis of an unknown is the identification of the elements present, i.e., the qualitative analysis. Qualitative x-ray analysis is often regarded as straightforward, meriting little attention. The reader will find far more references to quantitative analysis than to qualitative analysis, which has been relatively neglected in the literature, with a few exceptions (e.g., Fiori and Newbury, 1978). It is clear that the accuracy of the final quantitative analysis is meaningless if the elemental constituents of a sample have been misidentified. As a general observation, the identification of the major constituents of a sample can usually be done with a high degree of confidence, but, when minor or trace level elements are considered, errors can arise unless careful attention is paid to the problems of spectral interferences, artifacts, and the multiplicity of spectral lines observed for each element. Because of the differences in approach to qualitative EDS and WDS analysis, these techniques will be treated separately.