Tris(2-ethylhexyl)phosphate as an extractant for quadrivalent tin, with subsequent determination with pyrocatechol violet in alloy samples

Abstract

Abstract. The solvent extraction of tin(IV) from chloride media with tris(2-ethylhexyl)phosphate is presented. Tin(IV) is extracted quantitatively from 2.75-3.20 mol dm-3 hydrochloric acid using 6.38-6.91 mol dm-3 tris(2-ethylhexyl)phosphate dissolved in toluene as an extractant. After back-extraction of tin(IV) with water from the tris(2-ethylhexyl)phosphate phase, it is estimated spectrophotometrically following complexation with pyrocatechol violet. The recommended range for determination of tin(IV) is 10-100 ~tg. The probable extracted species is SnC14" 2TEHP. The method is applicable to the analysis of alloy samples with a detection limit of 0.4 gg/ml (for 10 gg of tin) and a relative standard deviation between 0.21-0.32%.