Determination of fluorine by total reflection X-ray fluorescence in fluoride fluxes

Authors:

• Zuzanna Kowalkiewicz,
• Włodzimierz Urbaniak

Abstract

Total reflection X-ray fluorescence spectrometry (TXRF) is known as a state-of-the-art and fast-growing analytical technique. The spectral range of TXRF spectrometry encompasses elements from sodium to uranium. The object of this study was to develop, optimize, and validate the analytical method for fluorine in a form of calcium fluoride determination in fluoride fluxes by total reflection X-ray fluorescence spectrometry. The sample was lixiviated in acetic acid, then, the sample was filtered and the sediment and the filter were ignited at 650 °C. A portion of dried and ignited and weighed sample was placed in a plastic centrifuge tube. To this tube Triton X-100, Ga as internal standard and polyvinyl alcohol were added. The accuracy of the element determinations was estimated by comparison between obtained and certified values of the elements determined in the Certified Reference Materials of fluorite (fluorspar). The limit of detection for TXRF measurement is 4.26 μg F · dm−3 whereas the limit of quantification equals 12.78 μg F · dm−3. The variation coefficient that characterized the reproducibility of the measurement equals 16.94%. In addition to this, it was found that the uncertainty of results associated with the sample preparation process for TXRF measurement is negligible, compared to the measurement uncertainty at the measurement stage using TXRF spectrometry. The results of this work demonstrate the acceptable and fully satisfactory validation criteria such as limit of detection and quantification, accuracy, and precision