Liquid-liquid extraction, preconcentration and trace determination of selenium with rotaxane

Abstract

A rapid and sensitive method for the extraction and spectrophotometric determination of Se(IV) with [2]-(l ,10-bis trityloxy decane)(1, 4, 7, 10, 13, 16, 19, 22, 25, 28-decaoxa cyclotriacontane)rotaxane (TDDCR), has been described. Selenium forms a colourless complex with TDDCR which is extracted in chloroform (molar absorptivity 3.18×10³ l mol^- ¹cm^-1) and obeys Beer's law in the range of 0.62-16.25 ppm for Se(IV). The extract is directly inserted in the plasma for ICPAES measurement of selenium which enhances the sensitivity several folds with the detection limits of 1.5 ppb. The overall formation ((logβ₂<i>K</i>_e) and distribution (<i>K</i>e) constants calculated are 11.56±0.03 and 2.0±0.05×10^-8, respectively. Selenium has been separated and determined in presence of tellurium.