Spectrophotometric Determination of Lanthanum and Cerium in Mixed Rare Earths

A spectrophotometric method has been developed for the determination of lanthanum and cerium in the presence of large amqunts of heavy rare earths with p-acetylarsenazo. The rare earths, except lanthanum and eerium, are masked with EDTA and Zn-EDTA. This method has been applied to the analysis of synthetic samples and Longnan mixed rare earth oxides without any previous separation and satisfactory results were obtained.