High-efficiency photoreductive vapor generation of osmium

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 Fe3/2+. 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)(y)H-z.