Sample damage during X-ray fluorescence analysis—case study on ammonium salts in atmospheric aerosols

Abstract

Atmospheric aerosols can consist of, amongst others, compounds like NH₄NO₃ or (NH₄)₂SO₄. Such components can suffer radiation damage and/or evaporate during EDXRF measurements, providing errors on successively applied analysis. The aim of this work is to investigate the influence of measurements using conventional EDXRF on the volatile compounds and to compare it with the influence of polarized beam EDXRF using secondary targets (and hence indirect irradiation). The effect of different parameters (acquisition time, accelerating voltage, current and medium) on the concentration loss was studied. The measurements performed in vacuum during a long period lead to the highest losses of volatile compounds. The influence of direct irradiation was proved to be larger than the indirect variant.