Radiotracer method for quantifying the amount of platinum and rhodium deposited in automotive catalytic converters

Radiotracer methods have been developed to quantify the amount of platinum and rhodium deposited on automotive catalytic converters as a function of p roduction conditions. In particular, this study determined the effects of s elective adsorption and evaporation processes on the aqueous impregnation o f converters with platinum group metal salts. The radiotracers used in this study, Pt-191 and Rh-105, were produced by thermal neutron activation of P t and Ru. Chemical processing was performed to remove undesired radioactive products and to ensure that each tracer was in its appropriate chemical st ate. This radiotracer method has been shown to be capable of measuring the platinum and rhodium loading on an entire substrate with a precision better than +/- 0.5%. At this precision level, the influence of selective adsorpt ion and evaporation were determined. (C) 1999 Elsevier Science B.V. All rig hts reserved.