Measurement of Trace Amount of Cadmium Using a Portable Total Reflection X-Ray Fluorescence Spectrometer

Abstract

This note describes a method for detecting Cd L-lines from a trace amount of cadmium using a portable total reflection X-ray fluorescence spectrometer. When the measurement was carried out in vacuum, the Ar K-lines (Ar Kα line: 2.96 keV, Ar Kβ line: 3.19 keV) that overlap with the Cd L-lines (Cd Lα line: 3.13 keV, Cd Lβ line: 3.32 keV) were remarkably reduced and the Cd L-lines from an analyte containing 1 ng of cadmium were detected. Although the K Kα line (3.31 keV) also overlaps with the Cd L-lines, solid-phase extraction for removing potassium from a sample solution containing both cadmium and potassium led to significant reduction in the intensity of the K Kα line. A combination of solid-phase extraction and measurement in vacuum makes it possible to analyze a trace amount of cadmium using the portable spectrometer.