CHARACTERIZATION OF SCR-DENOX MATERIALS BY ICP-MS AND ICP-AES - COMPARISON WITH XRF AND NAA

A procedure for the determination of eleven macro constituents by ICP- AES and several trace elements by ICP-MS was developed to give quantit ative accurate analytical information on a large number of ceramic cat alyst samples used for the denitrification of flue gas from a power pl ant. The determination of macro and trace elements was done on the sam e solution derived from the lithium tetraborate (LTB) fusion of the sa mple. The accuracy of the proposed procedure was evaluated by analyzin g the samples by X-Ray fluorescence (XRF) and by Neutron Activation An alysis (NAA). The results obtained by ICP-AES and XRF were compared by two different statistical models: the least squares linear regression (LR) and maximum-likelihood fitting of a functional relationship (MLF R). The examples reported in the present paper show that the applicati on of an incorrect statistical model can lead to erroneous conclusions regarding the accuracy of the tested methods. The MLFR function assur es the best fit for the experimental data allowing a realistic evaluat ion of the accuracy of all methods.