Quantitative analysis of platinum group metals using X-ray fluorescence spectrometry

Abstract

X-ray fluorescence (XRF) spectrometry was used to determine the platinum, palladium and rhodium contents in spent automotive catalyst and in two National Institute of Standard and Technology Standard Reference Materials (NIST SRMs) referred to as used auto catalysts. The XRF technique has proven to be a fast, effective and accurate method for determining not only these platinum group metals (PGM) but also other solid materials that are less soluble by wet digestion. The detection limits of XRF analyses are better than those of inductively coupled plasma mass spectrometry, which usually requires significant dilution to avoid high dissolved solid concentration. However, the XRF technique suffers from a strong matrix-dependent problem. The objective of this study was to examine the applicability of XRF for PGM analysis where the sample matrix is not exactly the same as the standard materials. This study compared the effect of various matrices, including alumina, iron, copper and nickel, on the determination of PGM.