High-efficiency photoreductive vapor generation of osmium

Abstract

A novel, high yield (91 ± 5%) photochemical vapor generation (PVG) method is reported for Os, achieved via photo-reduction reactions in a 1% CH₃COOH medium containing 50 mg L⁻¹ Fe^3/2+. A sample flow rate of 2 mL min⁻¹ delivered to a flow-through photoreactor provided a 21 s irradiation time prior to passage of the volatile product to an inductively coupled plasma mass spectrometer for detection at m/z 192. A method detection limit of 0.16 pg mL⁻¹ was achieved, a 10-fold enhancement over that obtained using parallel photo-oxidation synthesis of OsO₄ from a 5% HNO₃ medium. Precision of replicate measurement was 4% (RSD) at 10 ng mL⁻¹. Although the identity of the product has not yet been ascertained by GC-MS, based on the chemistry of Os and the reaction conditions, as well as its difference in volatility from OsO₄, a carbonyl or alkyl-substituted carbonyl is suspected e.g., Os_w(CO)_x(CH₃)_yH_z.