Three-dimensional distribution analysis of platinum, palladium and rhodiumin auto catalytic converters using imaging-mode laser-induced breakdown spectrometry

Laser-induced breakdown spectrometry (LIBS) is reported here as an effectiv e technique to describe the volume distribution of platinum, rhodium and pa lladium in catalytic converters installed in motor vehicles. Using the seco nd harmonic output of a Nd:YAG laser and a CCD-based atomic emission spectr ometer, LIES is used in multielemental, imaging-mode to permit the simultan eous analysis of the several elements present in the converter, including t he internal standard. The data are reported with a lateral resolution of 1. 75 mm over a fresh catalytic structure which is 128 mm long. The concentrat ional variability of the platinum group metals (PGMs) varies in the range s imilar to 3-23% relative standard deviation depending on the element, the s ubstrate and the direction investigated. The causes of the dispersion obser ved are discussed. (C) 2001 Elsevier Science B.V. All rights reserved.