Trace analysis of cadmium in rice by the selective excitation of L-Shell X-ray fluorescence

Abstract

The trace analysis of cadmium in rice was carried out by using L-shell excitation of X-ray fluorescence analysis. To reduce the influence of co-existing potassium, the excitation X-ray energy was selected below the absorption edge of potassium. It was found that the remaining background was from resonant inelastic X-ray scattering (RIXS) from potassium. The excitation X-ray energy dependence of the RIXS spectra from KCl was measured, and the optimized X-ray energy was 3580 eV. Optimization of the sample support was also investigated, and the rice flour was fixed onto a film of 6 μm thick polypropylene with polyvinyl acetate. The detection limit of cadmium in rice was 0.34 ppm under the optimized condition. © 2011 The Japan Society for Analytical Chemistry.