Study of ternary thorium complexes with some triphenylmethane reagents and cationic surfactants

Nine ternary thorium systems with Chrome Azurol S (CAS), Eriochrome Cyanine R (ECR) and Pyrocatechol Violet (PV) and the cationic surfactants cetyltrimethylammonium (CTA), cetylpyridinium (CP) and zephiramine (zeph) ions were examined as basis for spectrophotometric method for the determination of Th. Chrome Azurol S (with CP or CTA as the third component of the system) is recommended for the determination of thorium (the molar absorptivity for the method with CAS and CP is 1.40x105 l mol-1 cm-1) and other transition metal ions hydrolysed in neutral or weakly acidic media. Ternary systems with ECR (and mainly with zeph) can form the basis of sensitive spectrophotometric methods for the determination of some light main group metal ions. (author)