Observations on the determination of osmium by inductively-coupled plasma atomic emission spectroscopy.
Osmium tetroxide gives rise to very characteristic atomic emission properties. In acidic samples it gives much higher sensitivity than that given by the lower oxidation states (IV, III, II). However, in alkaline medium (pH 10.5) its atomic emission sharply decreases, and the sensitivity is the same as that for the other oxidation states. It has been shown that there is a direct relation between these characteristics of OsO(4) solutions and pH. With increasing pH the intensity of its atomic emission decreases, the electrode potential of its solutions drops sharply and the molecular absorption of radiation at 193 nm undergoes a hyperchromic and bathochromic shift. The volatility of OsO(4) has also been studied, and found to be minimum at around pH 9.5. This favours its determination at this pH.
Lopez-Molinero
A
A
Department of Analytical Chemistry, University of Zaragoza, 50009 Zaragoza, Spain.
Castillo
J R
JR
Mermet
J M
JM