Determination of trace ruthenium by catalytic kinetic spectrophotometry with azophloxine
MENG Qing-lun, WANG Ai-xiang*
Shandong Provincial Key Laboratory of Soil Conservation ＆ Environmental Protection, School of Chemistry and Chemical Engineering, Linyi University, Linyi 276005, China
Abstract：In phosphorie acid medium, trace ruthenium can sensitively catalyze potassium bromate to oxidize azo phloxine fading and based on this fact, a novel method for determining trace ruthenium is established. Through the experiment, the optimum reaction condition and kinetic parameter of the catalytic fading reaction was confirmed. At the wavelength of 528 nm, the mass concentration of ruthenium in 3-10 μg/L had excellent linearity with the absorption difference of catalytic and non-catalytic reaction. The linear correlation coefficient was 0.995 4, and the detection limit was 7.96 × 10-8 g / L. The reaction rate constant was 3.30×10-3 /s and the apparent activation energy was 193.72 kJ/mol. The interference experiment indicated the allowable amounts of other ions were more than 10 times of amount of ruthenium. The method combined with distillation separation was successfully applied for determining ruthenium in ore and metallurgical products with the RSD less than 1.9% (n=6) and the recovery between 98.6%-104.0%.
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