A somewhat different fundamental parameters approach to EDXRF quantification of solid environmental samples

Abstract

AbstractIn the presented elemental quantification of thick and intermediate thick solid environmental samples by energy dispersive X‐ray fluorescence (EDXRF), enhancement‐corrected elemental concentrations are evaluated and quantitative absorption parameter of low‐Z residual matrix in the sample is determined. The quantification is based on the analysis of real samples by a computer programme where, by definition, the total sample matrix is considered to be composed of measured elements and a residual matrix. As input, the measured fluorescent intensities of elements are used together with additional reference data of experimental absorption at single energy or the known concentration of internal standard in the sample. Basic equations developed by Sherman and other authors are used, involving fundamental parameters (FP) and instrumental constants obtained by the established calibration procedure. The quantification is performed by iteration of elemental concentrations and enhancement factors, but includes in absorption correction calculations elemental concentrations and absorption in the selected residual matrix. The absorption in any low‐Z residual matrix is a smooth function of energy characterised by a single parameter. Including residual matrix in the quantification affects the calculated elemental concentrations (also internal standard) and absorption in the sample. By comparing in consecutive iterations the fit of these parameters with given reference data, the quantification results and the proper selection of residual matrix are confirmed. The validation is performed by measuring standard reference materials: accuracy between 2% and 8% is obtained, compatible with accuracy obtained by other FP approaches. By the presented approach, the well‐known difficulties in XRF quantification due to the presence of light elements in the sample are remedied.