罗丹明B-Os(Ⅳ )-KIO_4催化动力学光度法测定微量锇

Catalytic Kinetic-Spectrophotometric Determination of Trace Osmium in the Rhodamin B Osmium(Ⅳ)-Potassium Periodate System

研究发现在酸性条件下,微量Os(Ⅳ)对高碘酸钾氧化罗丹明B褪色反应具有显著的催化作用,并以此为指示反应建立了测定微量锇的催化光度法.此反应的最佳条件为:10.0mL溶液中含0.10mol·L-1H2SO40.50mL,0.010mol·L-1KIO41.50mL,0.010%罗丹明B0.80mL,(90±0.5)℃水浴加热20min.方法的检测限为2.0×10-7g·L-1,Os(Ⅳ)含量在0.20～7.00μg·L-1范围内服从比耳定律.此方法已用于贵金属样品中微量锇的测定。

A spectrophotometric method has been reported for the detemination of trace of Os(Ⅳ),besed on the catalytic action of Os(Ⅳ) on the oxidation fading between RB and KIO 4 in the presence of H 2SO 4.Thebest conditions are that in 10?mL Os(Ⅳ) solution contain 0.5?mL 0.10?mol·L -1 H 2SO 4,1.5?mL 0.010 mol·L -1 KIO 4,0.80?mL 0.010% RB and the solution must be heated at (90±0.5)℃ for 20?min in the water bath.Beer's law is obeyed in the range from 0.20—7.0?μg·L -1 for Os(Ⅳ) and the detection limit is 2.0×10 -7 ?g·L -1 at 555?nm.The method has been applied to the determination of Os(Ⅳ) in samples of noble metal.The RSD ( n =8) were 1.34%—2.63% and recoveries were 97.5%—103.0%.