Catalytic kinetic spectrophotometric method for determination of trace ruthenium with Ru(III)-malachite green-KIO4 system

A kinetic spectrophotophotometric method for the determination of trace amounts of ruthenium based on the catalytic effect of Ru(Ⅲ)on the oxidation of malachite green by potassium periodate in H2SO4 medium heated in a water bath of 75℃ is reported.The linear of the method is 0.50～8.0 μg/L.and the detection limit for Ru(Ⅲ) is 1.43×10-10 g/mL.The apparent activation energy of catalytic reaction is found to be 20.69 kJ/mol.The rate constant is 5.55×10-3s-1.The interference from over 40 foreign ions is tested and most of the common ions can be tolerated.The method is applied to the determination of ruthenium in two metallurgical product samples with the relative standard deviations of 1.6% and 1.9%(n=6),the recoveries of 99.5% and 99.2%,respectively.