This article presents the results of a study of the complex formation of samarium(III) with 3-(2-hydroxy-3-sulpho-5-(nitrophenylhydrazo)pentan-2,4-dione (R) in the presence and absence of surfactants: cetylpyridinium chloride (СPСl), cetylpyridinium bromide (СPBr), cetyltrimethylammonium bromide (CTMABr). The ratio of the reacting components in the composition of the same- (1:2) and mixed-ligand (1:2:2) compounds was established. The range of compliance with Beer's law was determined. The specific electrical conductivity of the studied complexes was studied by the method of conductometric titration. A technique for the photometric determination of samarium in monazite has been developed. The acidity of the solutions was monitored on an I-130 ion meter with an ESL-43-07 glass electrode. The optical density of the solutions was measured on a LAMBDA-40 spectrophotometer (Perkin Elmer) and a KFK-2MP photocolorimeter in a cuvette with a layer thickness of 1 cm. The specific electrical conductivity of the solutions was measured on a Mettler Toledo conductometer. It was found that in the presence of third components analytical parameters of mixed-ligand complexes. Results of investigation were used for determination of Sm(III) in monacite

doi.org/10.32737/0005-2531-2023-1-169-175