Determination of trace elements in ZnS–Ag+ and ZnS–Cu+ type luminophore materials by X-ray fluorescence spectrometry following trace-matrix separation and co-precipitation

Abstract

The multi-element method to determine trace elements Ag, Co, Fe, Cr and Cu in ZnS-type luminophore materials by X-ray fluorescence spectrometry is presented. Co-precipitation on a carrier has been applied to separate analyte elements from zinc and to minimize absorption effects. The developed method is based on dissolution of the zinc matrix in excess of a concentrated (ca. 12%) solution of NaOH and precipitation of cobalt, iron, chromium, copper and silver on the carrier MnO₂ + Mg(OH)₂. The precipitate is collected on a membrane filter. The internal standard was used to check the inhomogeneity of the mass per unit area. The determined concentrations in analyzed materials are in good agreement with the value obtained using ICP-AES and AAS.