Determination of trace Ruthenium(III) by catalytic kinetic spectrophotometry with malachite green

In sulfuric acid and at a temperature of 80 ℃,the depigmentation reaction of potassium periodate oxidizing malachite green can be greatly catalyzed by ruthenium.The optimal experimental conditions of this reaction were discussed and a new method of catalytic kinetic spectrophotometric determination for ruthenium was established.The absorbency difference ΔA between non-catalytic absorbency A0 and catalytic absorbency A remains a good linear relationship with mass concentration of ruthenium(Ⅲ) in the range of 0.1～1.5 μg/25 mL,and the detection limit is 4.31×10-10 g/mL.The dynamic parameter was also measured,and the result showed this reaction was first order reaction.The apparent rate constant is 3.52×10-4 /s,and the apparent activation energy is 46.97 kJ/mol.This method was applied to the determination of ruthenium in sample catalysts with satisfactory results,and the recoveries were between 98.6%～104.8% which met the requirement of trace analysis.