Fundamental parameters method for determination of rare earth elements in apatites by wavelength-dispersive X-ray fluorescence spectrometry

Abstract

The determination of rare earth elements (REE) in small samples of various apatites (hydroxylapatites, carbonate-hydroxyl-fluorapatites, fluor-carbonate-hydroxylapatites, fluorapatites, fluor-meta-apatites) by wavelength-dispersive X-ray fluorescence spectrometry (WDXRF) is presented. A small amount of the analyzed material is digested in aqua regia and then the solution obtained is pipetted onto a membrane filter. Absorption effects of the matrix elements, e.g. Ca, P, and the membrane filter are determined using an emission–transmission method. Analysis is performed using a lanthanum standard sample and theoretical calculation of the radiation intensity of REE. Therefore, standard samples for each REE are not required. Overlap of the REE peaks is also corrected theoretically using the spectrometer resolution and an approximation of the peak shape by a Gaussian function.