Guanidinium-containing silica-based anion exchangers show great potential for the selective extraction of platinum group metals from authentic precious metal refinery solutions. The pH range for selective palladium extraction over Cu and Ni was found to be increased by as much as 2 pH units compared to previously reported (poly)amine-containing ion exchangers without efficiency loss. (c) 2005 Elsevier B.V. All rights reserved.