氯磺酚偶氮罗丹宁催化动力学光度法测定痕量钌

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425 nm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8.1×10-9g/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9.74×10-3/s,表观活化能为82.09 kJ/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。

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

Trace Ru(Ⅲ) could sensitively catalyze the fading reaction of chlorosulphophenol azo rhodanine (CSPAR) with KClO_3 in H_2SO_4 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 Ru(Ⅲ) 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 %.