Glass Bead Sample Preparation forXRF

Abstract

X‐ray fluorescence spectrometry (XRF) is often used for bulk elemental analysis. A commercial apparatus equipped with automatic calculation software can obtain semiquantitative composition values of major and minor elements in a solid sample without sample preparation. However, reliable and traceable determination requires strict analytic procedures including appropriate sample preparation and a favored calibration curve method. The glass bead sample preparation technique is much better suited for such determination than direct measurement of a solid sample with no sample preparation or powdered sample preparation such as pressed briquettes and loose powder. The fluorescent X‐ray intensity varies with physical and chemical factors such as heterogeneity of the measured sample and matrix effects including X‐ray absorption and enhancement on the measured specimen. These interfering factors can be largely overcome using glass bead sample preparation including sample fusion with a borate matrix. Then homogeneous specimens of sample and standard can be prepared easily for oxidizing samples such as geochemical igneous rock, environmental soil, archaeological ceramics, and industrial raw materials such as iron ore. This article presents details of glass bead sample preparation for reliable and accurate results. Calibration curve methods with appropriate standards, especially synthetic standard glass beads with chemical reagents, are also described.

Absorption‐free calibration on X‐ray fluorescence analysis of high‐speed steel with glass bead preparation

“…A glass bead is generally prepared to reduce the X‐ray absorption because of the dilution effect by a flux agent of light elements such as lithium, boron, and oxygen. Higher flux‐to‐sample ratio causes greater dilution effect to suppress the X‐ray absorption effectively; however, it also degrades the sensitivity and precision in the XRF analysis. It is thus important to use an optimized flux‐to‐sample ratio for reliable XRF quantification …”

“…In general, the concentration of an analyte in a glass bead specimen ( c analyte = w analyte / w glass bead , where c analyte is the analyte concentration in the glass bead, w analyte is an amount of analyte, and w glass bead is an amount of the glass bead) is used for the calculation of XRF quantification . Glass beads with the same flux‐to‐sample ratio ( w flux / w sample , where w flux is an amount of the flux and w sample is an amount of a sample) have to be prepared to use a calibration curve.…”

“…An analytical value in mass% is obtained by c analyte × (1 + w flux / w sample ) × 100. In the present study, we focused on the amount of an analyte ( w analyte ) itself for a calculation parameter. When the X‐ray absorption in a glass bead specimen can be ignored, the amount of lithium tetraborate ( w flux ) has not to be determined strictly on the XRF quantification, thus leading to a calibration relationship between w analyte and the XRF intensity independent of the w flux / w sample .…”

Investigation of Soils and Pine Needles Using WDXRF and TXRF Techniques for Assessment of the Environmental Pollution of Shelekhov District, Eastern Siberia, by the Aluminum Industry and Heat Power Engineering

“…The WDXRF method is a common technique for the determination of major elements in geological objects. This method primarily uses two sample preparation techniques: pressing of powder to a pellet [31] and fusion of powder with flux to obtain a homogeneous glass disk [32]. Fusion is a versatile technique for WDXRF analysis of soils due to its ability to minimize the effects of particle size and mineralogical composition.…”