Analysis of Nanograms of Cadmium Using a Portable Total Reflection X-Ray Fluorescence Spectrometer

Abstract

Nanograms of Cd are measured with a portable total reflection X-ray fluorescence spectrometer. A relationship between a detection limit for Cd and counting time is investigated. A Cd detection limit is improved with the increase in counting time, and a detection limit of 1 ng is achieved when a measurement is performed for 1800 s. Cadmium quantitative performance is shown. Yttrium is used as an internal standard element, and the Cd Kα/Y Kα intensity ratio is linear with mass of Cd in the range from 10 to 1010 ng. Detection limits for Cd obtained with or without a 30 μm thick Mo absorber are compared. The spectral background is reduced using the Mo absorber, leading to an increase in the signal to background ratio of the Cd Kα line. However, the use of the Mo absorber results in a decrease in the net intensity of the Cd Kα line. Therefore, a detection limit obtained with the Mo absorber is as low as that obtained without an absorber.