Spectrophotometric determination of samarium(III) with chrome azurol S in the presence of cetylpyridinium chloride

A sensitive, simple method for the determination of trace amounts of samari um by spectrophotometry is described based on the formation of the samarium -chrome azurol S (CAS) complex in micellar medium. The molar absorptivities of the complexes at pH 7.5 at 505 nm were 3.6 x 10(4) and 1.4 x 10(5) 1 mo l(-1) cm(-1) for water media and cetylpyridinium chloride (CPC), respective ly. Beer's law is obeyed from 0.05-2 mg 1(-1) of samarium at 505 nm as Sm-C AS-CPC complex. Optimal conditions such as reagent amounts, and pH for the samarium determination were reported. The effects of foreign ions were also investigated. The proposed method was successfully applied to the determin ation of samarium contents in synthetic samples. (C) 2000 Elsevier Science B.V. All rights reserved.