N-(4-Hydroxy- 3-methoxybenzylidene) hydrazine carbothioamide as a selective and sensitive reagent for the rapid spectrophotometric determination of osmium(VI)

Abstract

N-(4-Hydroxy- 3-methoxybenzylidine)hydrazine carbothioamides is proposed as a selective and sensitive reagent for the rapid spectrophotometric determination of osmium (VI). The reagent forms a brownish-yellow complex with osmium(VI) at room temperature in 1-4<em>M </em>acetic acid medium. The complex exhibits absorption maximum at 364 nm with a molar absorptivity of 1.2 x 10⁵ dm³ mol^-1 cm^-1. Beer's law is valid over the concentration range of 0.02-1.2 ppm of osmium(VI) with an optimum concentration range of 0.1-1.1 ppm. The apparent stability constant of the complex is log <em>K </em>= 6.79 ± 0.1 at 28°C. The method has been used for the determination of osmium in sy-serskite.