Role of the self-validation principle of NAA in the quality assurance of bioenvironmental studies and in the certification of reference materials

摘要

It is well recognized that one of the most important ways of verifying or harmonizing analytical data is to obtain results from independent or diverse methods. Neutron activation analysis (NAA) is already known as one of the most favourable techniques for obtaining reliable data in intercomparisons, the certification of reference materials and other quality assurance steps on account of its inherent properties. However, in the paper it is emphasized that NAA also possesses the additional in-built and unique advantages, so far little exploited, of being able to perform in independent analytical modes or methdological routes, thus providing a means of internally validating or cross-checking the data it generates. This has been termed the self-validation principle or approach. In the paper the self-validation principle is explained and the elements of analytical independence arising from the isotopic character of NAA, its different modes of instrumental (non-destructive) and radiochemical operation and additional alternative strategies involving diversity of activation, separation and counting are examplified. A table listing alternative activation routes for about 30 elements is included. The use of self-validation to provide consistent analytical data from different methodologies of activation analysis is illustrated with concordant results obtained for certified or standard reference materials.