A COMPARISON OF THE PERFORMANCE OF A FUNDAMENTAL PARAMETER METHOD FORANALYSIS OF TOTAL-REFLECTION X-RAY-FLUORESCENCE SPECTRA AND DETERMINATION OF TRACE-ELEMENTS, VERSUS AN EMPIRICAL QUANTIFICATION PROCEDURE

The performance has been compared of two different quantification meth ods - namely, the commonly used empirical quantification procedure and a fundamental parameter approach - for determination of the mass frac tions of elements in particulate-like sample residues on a quartz refl ector measured in the total reflection geometry. In the empirical quan tification procedure, the spectrometer system needs to be calibrated w ith the use of samples containing known concentrations of the elements . On the basis of intensities of the X-ray peaks and the known concent ration or mass fraction of an internal standard element, by using rela tive sensitivities of the spectrometer system the concentrations or ma ss fractions of the elements are calculated. The fundamental parameter approach does not require any calibration of the spectrometer system to be carried out. However, in order to account for an unknown mass pe r unit area of a sample and sample nonuniformity, an internal standard element is added. The concentrations/mass fractions of the elements t o be determined are calculated during fitting a modelled X-ray spectru m to the measured one. The two quantification methods were applied to determine the mass fractions of elements in the cross-sections of a pe at core, biological standard reference materials and to determine the concentrations of elements in samples prepared from an aqueous multi-e lement standard solution. (C) 1998 Elsevier Science B.V.