Simultaneous determination of chlorine and sulfur in geochemical reference samples by wavelength dispersive X-ray fluorescence spectrometry

Abstract

A simple and rapid wavelength dispersive X-ray fluorescence spectrometry method was developed for simultaneous determination of Cl and S in geochemical reference samples. Spectral line shifts and matrix effect of different inorganic sulfur species were studied by WD-XRF. Analysis of the spectral lines in the P Kα–Cl Kα wavelength range confirmed that the Mo Lγ1 line overlaps with the Cl Kα line and Mo Lα line interferes with S Kα line. The effect of repeated detection on the measurement results was analyzed. The detection limits for Cl and S were 5.37 mg kg⁻¹ and 5.41 mg kg⁻¹, respectively. The relative deviations of Cl and S determination were −8.6–8.8% and −7.6–8.2%, the %RSD values were lower than 10%, showing good accuracy and precision. The results of WD-XRF, spectrophotometry, ICP-OES and combustion-IR detection were compared. The fitness for purpose of the results was evaluated by the quality criteria test proposed by the International Geological Correlation Programme (IGCP), from which it can be confirmed that considering the application of geochemical mapping, the method of determining Cl and S by WD-XRF is adequate.