A systematic study has been made on the reducing power of amalgamated copper powder in hydrochloric acid solution for palladium,
platinum, rhodium, iridium, gold and silver. In order to apply this method to the activation analysis of palladium, platinum
and rhodium in industrial concentrates which contain a large amount of ‘base elements’, the behaviour of palladium, platinum
and rhodium in the presence of the ‘base elements’ has also to be considered.