Spectrophotometric determination of osmium and ruthenium with N-benzoyl-N'-methylphenyl selenourea

N-benzoyl-N-methylphenyl selenourea is recommended as a chelating agent for the spectrophotometric determination of osmium(VI) and ruthenium(III). The reagent forms a reddish-brown complex with ruthenium(III). Quantitative extraction of ruthenium is obtained from a solution at 0.8M-3.0M hydrochloric acid. The chloroform extract of ruthenium complex shows maximum absorption at 460 nm and Beer's law is obeyed over the concentration ranging from 0.65 to 9.81 g Ru(III)/ml. The reagent forms 3:1 complex with ruthenium. The advantage of the use of N-benzoyl-N'-methylphenyl selenourea as a spectrophotometric reagent for both osmium and ruthenium lies in the fact that these metal ions can be determined in presence of all base metals and large excess of all other platinum metals. Simultaneous determination of osmium and ruthenium is possible with the chelating agent. (auth.)