Sequential separation of selenium(IV) from tellurium(IV) by solvent extraction with N-n-octylaniline: Analysis of real samples

A simple solvent extraction study of selenium(IV) was conducted. Selective and quantitative extraction of selenium(IV) by N-n-octylaniline in xylene occurred from 0.4 to 0.6 M hydrochloric acid medium. Selenium(IV) was back extracted with 1:1 ammonia. The effect of concentration of acid, N-n-octylaniline, the role of various diluents, stripping agents, loading capacity of N-n-octylaniline, equilibrium time, aqueous to organic volume ratio on the extraction of selenium(IV) was studied. Selenium(IV) was extracted into the organic phase by ion-pair formation complex as [RŔNH^+ 2HSeO^- 3] (org). The method is free from interferences due to commonly associated elements and permits the separation of selenium(IV) from tellurium(IV) as well as other metal ions. It was used for the determination of selenium(IV) in synthetic mixtures, synthetic mixtures corresponding to alloys and pharmaceutical samples.