Spectrophotometric determination of osmium with 4(5)-D-arabinotetrahydroxybutylimidazoline-2-thione

Abstract

4(5)-D-Arabinotetrahydroxybutylimidazoline-2-thione (THBIT) forms a bluish violet complex in sulphuric, perchloric or hydrochloric acid media that has been utilised for the determination of osmium by spectrophotometry. The colour system has its absorption maximum at 530 nm and obeys Beer's law over the range 1–47 µg ml^–1 of Os in 0.01–3.6 M H₂SO₄. The optimum range is 7–35 µg ml^–1. The molar absorptivity is 4.5 × 10³ l mol^–1 cm^–1. The method has a wide range and is simple, rapid and free from interferences from many metals ions, including some platinum metals.