Investigation of the formation of ternary gallium, indium and thallium(3) complexes with some triphenylmethane reagents and cationic surfactants

Conditions for the formation of the ternary gallium and indium complexes with chrome azurol S, eriochrome cyanine R and pyrocatechol violet in the presence of cationic surfactants: cetyltrimethylammonium bromide, cetylpyridinium chloride and zephiramine have been established. Thallium(3) forms no ternary complexes with these reagents because of its too ''soft'' acid character. The new spectrophotometric determination methods of Ga and In based on the ternary systems Ga-ECR-zeph (ε=1.23 x 105 l x mol-1 x cm-1 at 580 nm) and In-CAS-zeph (ε=1.14 x 105 l x mol-1 x cm-1 at 620 nm) are developed. 3 μg of Ga can be determined by means of the method in the presence of 20 μg of In or even 500 μg of Tl, while 5 μg of In - in the presence of 100μg of Tl. 3 figs., 2 tabs., 20 refs. (author)