氧化偶氮胂Ⅲ褪色光度法测定钒

摘要

A new method for spectrophotometric determination of trace amount of vanadium based on decolorizing reaction of arsenazo Ⅲ oxidized by V(Ⅴ) in H2SO4 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 1.14×104 L·mol-1·cm-1.The linear range is 0～10 mg/L for V2O5.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).%在H2SO4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530 nm，表观摩尔吸光系数为1.14×104 L·mol-1·cm-1，V2O5的测定范围为0～10 mg/L。方法用于铁矿石中微量钒的测定，其RSD(n=5)为0.53%～2.05%。