Two standardisation techniques: Direct (DS) and Piecewise Direct Standardisation (PDS) were applied to multivariate models developed using X-ray spectra. The data were obtained for the determination of Ca and Fe in flying ashes from brown coal using low resolution XRF analysis. The analyser AF-20 was used with an argon proportional counter and a Cd-109 radioisotope source. Number and composition of samples from the calibration set were selected. Root mean square error of prediction (RMSEPr) was used as a criterion for assessment of the standardisation quality. The best performance was obtained for the PDS method using 5 samples chosen with the leverage method. The RMSEPr value was 4 times lower for Ca determination and 2 times lower for Fe compared with the results without standardisation.
Software package was designed for fast computation of the standardisation transform. The program can be used when the instrument parameters have changed as well as for calibration of the new instrument.