The Extraction Spectrophotometric Determination of Scandium with Xylenol Orange and Ethyltridodecylammonium Bromide

Abstract

A spectrophotometric method of determination of scandium was studiedby the solvent extraction of scandium-xylenol orange chelate into xylene solution of ethyltridodecylammonium bromide (ETDA). The scandium-XO-ETDA complex was extracted into aromatic hydrocarbons such as benzene, toluene, xylene, but not into polar solvents such as, n-butanol, ethylacetate, methylisobutylketone, and nitrobenzene. The extracted complex had an absorption maximum at 520 nm. Its maximum extraction was obtained when the pH of the aqueous phase was adjusted to 6.O-6.7. The extraction rate of the complex was fast and equilibrium was attained by shaking for 10 sec. Beer's law was seen up to 7.0μg scandium per 5.0ml of xylene. The molar absorption coefficient of the complex was 2.7X104 cm-1.mol-1.l at520 nm. Composition of the complex was estimated to be Sc:XO:ETDA=1:1:2 by the mole ratio, continuous variation and mobile equilibrium methods, Consequently it may be assumed that the ternary complex was an ion association system with [ScHR2-]((ETDA+)2) structure, Triethylenetetramine and o-phenanthroline can be used for the masking of many metal ions, but the presence of vanadium, aluminum, beryllium, thorium, zirconium, uranium, bismuth, lanthanum, nitrate, perchlorate, citrate, EDTA interfered the determination seriously.