Catalytic spectrophotometric determination of trace ruthenium with Ru(III)-methyl violet-KIO4 system

A kinetic spectrophotometric method for the determination of trace ruthenium based on the catalytic effect of Ru(Ⅲ) on the oxidation of methyl violet by potassium periodate in H2SO4 medium and in a water bath of 75 ℃ was reported.The linear range of the method is 0.002-0.01 μg/mL,and the detection limit is 5.0×10-10 g/mL.The apparent activation energy of catalytic reaction is found to be 14.21 kJ/mol,and the apparent rate constant is 2.36×10-3 s-1.The interferences of over forty foreign ions were tested and most of the common ions were tolerable.The method has been applied to the determination of ruthenium in ore samples,and the results are in accordance with the recommended values.