氯磺酚偶氮罗丹宁催化动力学光度法测定痕量钌

Determination of trace ruthenium by catalytic kinetic spectrophotometry with chlorosulphophenol azo rhodanine

H2SO4介质中，水浴85℃条件下，痕量Ru（Ⅲ）能灵敏地催化KClO3氧化氯磺酚偶氮罗丹宁（CSPAR）的褪色反应，且褪色程度与钌含量在一定范围内成正比，据此建立了催化动力学光度法测定痕量钌的新方法。以425nm为分析波长，Ru（Ⅲ）含量在0．007～0．15μg／mL范围内呈线性关系，方法的检出限为8．1×10g／mL。动力学常数测定实验结果表明，该催化反应对钌为一级反应，反应速率常数为9．74×10／s，表观活化能为82．09kJ／mol。方法用于钌碳催化剂样品中痕量钌的测定，结果的相对标准偏差为2．1％，加标回收率在96％～103％之间。

Trace Ru（Ⅲ） could sensitively catalyze the fading reaction of chlorosulphophenol azo rhodanine （CSPAR） with KClO3 in H2SO4 medium in water bath at 85 ℃, and the fading level was in direct proportion to Ru（Ⅲ） in certain content range. Based on this, a novel determination method of trace ruthenium was established by catalytic kinetic spectrophotometry. With 425 nm as analytical wavelength, the content of Ruff） showed linearity in the range of 0. 007-0.15 μg/mL. The detection limit of this method was 8.1× 10^-9 g/mL. The test results of kinetic constant indicated that this catalytic reaction was first order reaction for Ru（Ⅲ）. The constant of reaction rate was 9.74× 10^-3/s and the apparent activation energy was 82.09 kJ/mol. This method was applied to the determination of trace ruthenium in Ru/C catalyst sample. The relative standard deviation （RSD） was 2.1%, and the recovery of standard addition was 96 %-103 %.