Determination of osmium by the sorption-X-ray fluorescence technique

Sorption of osmium(IV, VI) on complexing sorbents POLYORGS XXIV, POLYORGS 32 M, and POLYORGS 32 V and on the PVA-PGMA-PEPA sorbent from alkaline and hydrochloric acid solutions is studied. It is demonstrated that equilibrium in systems under study is attained within 40 min for the POLYORGS XXIV sorbent and within 2.5 h for the POLYORGS 32 V sorbent and that the sorbents exhibit a sufficiently high sorptive capacity with respect to osmium: from 3.4 to 8 mg of Os(VI) in alkaline solutions and 2.2 mg of Os(IV) in acidic solutions. Optimal conditions of analysis of a concentrate on an EDX-771 energy-dispersive X-ray fluorescence spectrometer are revealed and, on this basis, a sorption-X-ray fluorescence method that provides the determination of osmium in a wide concentration range with the detection limit down to 10-6% is developed.