A differential pulse polarographic method for the determination of trace amounts of osmium(VIII) using a polarographic maximum wave

A differential pulse polarographic method for the determination of trace osmium(VIII) is described. In the presence of about 2000-times Cys, osmium(VIII) in a 1.0 mol/dm(3) hydrochloric acid solution exhibits a well-defined maximum wave, or peak at -0.85 V vs. SCE. The peak height in the presence of Cys was amplified about 1600-times. The peak height depends on the concentration of hydrochloric acid, and reaches its maximum in a concentration range of 0.75 to 1.25 mol/dm(3). Concerning the existence of Cys, the maximum wave, or peak, was complicatedly controlled by the adsorption, catalytic, and/or kinetic currents. Although Ag+, Cd2+, Cu2+, Hg2+, Pb2+ and Zn2+, which were highly affinitive with Cys, did not interfere with the osmium peak, an excess amount of Cu2+ did interfere. Osmium(VIII) was directly detected by this method over a concentration range of 8.0 x 10(-10) to 2.7 x 10(-7) mol/dm(3); the detection limit was 3.5 x 10(-10) mol/dm(3) (k = 3).