速差褪色动力学光度法同时测定钢中铬(Ⅵ)和锰(Ⅶ)

Simultaneous determination of chromium(Ⅵ) and manganese(Ⅶ) in steel by differential reaction rate kinetic spectrophotometry

研究了铬(Ⅵ)和锰(Ⅶ)氧化玫瑰桃红R的褪色反应。在硫酸介质中,50℃水浴加热条件下,铬(Ⅵ)和锰(Ⅶ)均能氧化玫瑰桃红R褪色,但褪色反应速率存在明显的差异,据此,建立了速差褪色动力学光度法同时测定钢铁中铬和锰的新方法。考察了褪色反应的最佳酸度,选择了反应的最佳实验条件,建立了比例方程。铬和锰的线性范围分别为0-10.0μg/mL和0-8.0μg/mL,在线性范围内铬和锰的加和性良好。方法应用于钢铁中铬和锰的同时测定,测定结果与认定值相符合,相对标准偏差(RSD)分别为:1.93%-3.70%,0.85%-2.11%。

The fading reaction of bordeaux-red oxidized by chromium（Ⅵ） and manganese（Ⅶ） is studied, In H2SO4 medium, both chromium（Ⅵ） and manganese（Ⅶ）can oxidize bordeaux-red at 50 ℃ with differential reactionrate. Based on this, a new differential reaction rate kinetic spectrophotometry for simultaneous determination of chromium（Ⅵ） and manganese（Ⅶ） is established. According to the ratio equation, the fitting acidity of fading reaction, reaction temperature and the amounts of bordeaux-red are checked. The linear range is 0 - 10.0 μg/mL for chromium（Ⅵ） and 0 - 8.0 μg/mL for manganese（Ⅶ）, respectively. The method has been applied to the simultaneous determination of chromium（Ⅵ） and manganese（Ⅶ） in steel samples with RSDs of 1.93 % - 3.70 % for Cr（V]）, 0.85 % - 2.11% for Mn（Ⅵ）. The determination results of this method consist with the certified values.