title: Simultaneous spectrophotometric determination of thorium and rare earth metals with m-carboxychlorophosphonazo (CPAmK) and cetylpyridinium chloride.
abstract: Th and rare earth elements (REE) react with m-carboxychlorophosphonazo (CPAmK) in the absence of cetylpyridinium chloride (CPC) to form colour complexes. The molar absorptivities for Th and Ce are 1.03 x 10(5) and 1.06 x 10(5) 1.mole(-1).cm(-1) respectively. In the presence of CPC, REE-complexes are not formed because of micellar masking, while Th gives a more sensitive reaction with CPAmK ( = 1.50 x 10(5)). Most of the foreign ions are tolerated in considerable amounts; 360-1000-fold amounts of rare earths do not interfere with the determination of Th. The optimum conditions of the complex-formation reactions and the compositions of Th-CPAmK complexes are described. A simple method is proposed for simultaneous determination of Th and rare earths without previous separation.
authors.affiliation: Department of Chemistry, East China Normal University, 3663, Zhong Shan Road (N), Shanghai 200062, People's Republic of China.
authors.forename: C G
authors.initials: CG
authors.lastname: Hsu
authors.forename: X M
authors.initials: XM
authors.lastname: Lian
authors.forename: J M
authors.initials: JM
authors.lastname: Pan