氧化偶氮胂Ⅲ褪色光度法测定钒

Spectrophotometric Determination of Vanadium by Bleaching Arsenazo Ⅲ

在H2 SO4介质中 ,V(Ⅴ )对偶氮胂Ⅲ有褪色作用 ,且褪色的程度与V(Ⅴ )的含量呈线性关系 ,由此建立了光度法测定V的新方法。方法的最大吸收波长为 530nm ,表观摩尔吸光系数为 1 .1 4× 1 0 4 L·mol- 1 ·cm- 1 ,V2 O5 的测定范围为 0～ 1 0mg/L。方法用于铁矿石中微量钒的测定 ,其RSD(n =5)为 0 .53%～ 2 .0 5%

A new method for spectrophotometric determination of trace amount of vanadium based on decolorizing reaction of arsenazo Ⅲ oxidized by V(Ⅴ) in H 2SO 4 medium was established. The fading in color is directly in proportion to the amounts of vanadium. The maximum absorption is at 530?nm and the apparent molar absorptivity is 1.14×10 4?L·mol -1 ·cm -1 .The linear range is 0～10?mg/L for V 2O 5.The method has been applied to the determination of trace vanadium in iron ores and the satisfactory results were obtained with precision of 0.53% ～2.05% RSD( n =5).