氧化偶氮胂Ⅲ褪色光度法测定微量锰的研究

PHOTOMETRIC DETERMINATION OF MICROAMOUNTS OF MANGANSE BY THE OXIDATIVE COLOR FADING OF ARSENAZO Ⅲ

Mn( )对偶氮胂 具有褪色作用 ,借此可以进行吸光光度法测定锰。试验表明 ,在0 .36～ 1 .2 6mol·L- 1 硫酸介质中 ,有色溶液的最大吸收波长为 550 nm,表观摩尔吸光系数为 1 .33× 1 0 4 L· mol- 1 · cm- 1 。锰量在 0～ 60μg/2 5ml范围内服从比耳定律。方法简单、快速、准确、选择性好 ,可用于测定某些地质样品中的微量锰。

It is found that in a 0.36~1.26mol·L -1 H 2SO 4 medium, the reagent arsenazo Ⅲ is oxidized by Mn(Ⅶ) leading to the decolorization of the reagent. The decrease of the color intensity is proportional to the amount of Mn(Ⅶ) present. The absorptive maxima lies at 550nm with an apparent molar absorptivity of 1.33×10 4. Beer′s law is obeyed in the concentration range of 0 to 60μg of manganese(Ⅶ) per 25ml. Based on this phenomenon, a method is proposed for the determination of traces of manganese in geological samples.