Catalytic kinetic methods for determining osmium (review)

Abstract

Catalytic kinetic methods for determining osmium are reviewed. It is shown that almost all indicator reactions used for catalytic kinetic determination of osmium are redox ones. As oxidizers, Ce (IV) ion, bromate, periodate, and iodate ions, and hydrogen peroxide are used, as a rule. As reducers, organic dyes are used in most cases; inorganic reducers, mainly arsenous acid and its salts, are used slightly less often. It is found that the pyrogallolphthalein oxidation reaction in the presence of polyoxyethylene glycol dodecyl ether is characterized by the best sensitivity for determining Os (VIII) (the detection limit is 5 × 10−5 ng/cm3). Techniques based on the reactions of As (III) oxidation by bromate, iodate, and periodate ions and N-methyl-n-aminophenol oxidation by hydrogen peroxide are very sensitive and selective. The most promising ways to improve the catalytic kinetic techniques for determining osmium are found.