APPLICATION OF REFERENCE MATERIALS FOR QUALITY ASSESSMENT IN NEUTRON-ACTIVATION ANALYSIS - USE OF INFORMATION-THEORY

It is generally accepted that an analytical procedure can be regarded as an information production system yielding information on the compos ition of the analyzed sample. Thus, information theory can be useful a nd the quantities characterizing the information properties of an anal ytical method may be applied not only as evaluation criteria but also as objective functions in the optimization. The usability of informati on theory is demonstrated on the example of neutron activation analysi s. Both precision and bias of NAA results are taken into account toget her with the possible use of reference materials for quality assessmen t. The influence of the above-mentioned parameters on information prop erties such as information gain and profitability of NAA results is di scussed in detail. It has been proved that information theory is espec ially useful in choosing suitable reference materials for the quality assessment of routine analytical procedures not only with respect to m atrix and analyte concentration in the sample but also to concentratio ns and uncertainties of certified values in the CRM used. In the extre me trace analysis, CRMs with relatively large uncertainties and very l ow certified concentrations can still yield rather high information ga in of results.