5-Br-PADAP为显色剂吸光光度法测定微量重铬酸根的研究  

ABSORPTIOPHOTOMETRIC DETERMINATION OF Cr_2O_7^(2-) WITH 2-(5-BROMO-2-PYRIDYLAZO)-5-DIETHYLAMINOPHENOL (5-Br-PADAP)

作　　者：尹洪宗[1] 崔彦[1] 刘葵[1] 

机构地区：[1]山东农业大学理学院,泰安271018

出　　处：《理化检验（化学分册）》2002年第9期464-465,共2页Physical Testing and Chemical Analysis(Part B:Chemical Analysis)

摘　　要：研究了 2 (5 溴 2 吡啶偶氮 ) 5 二乙氨基酚 (5 Br PADAP)在硫酸介质中质子化后与Cr2 O2 - 7形成二元离子缔合物的最佳条件 ,提出了测定微量Cr2 O2 - 7的吸光光度新方法 ,表观摩尔吸光系数ε580 =1.1× 10 5L·mol- 1·cm- 1。Cr2 O2 - 7浓度范围为 0～ 6 .2 4 μg·ml- 1。缔合物组成比为n(5 Br PADAP)∶n(Cr2 O2 - 7) =1∶1,方法应用于合金钢中铬的测定 。In a weakly sulfuric acid solution having its acidity between 0.12～0.16mol·L -1, dichromate ion (Cr 2O 2- 7) reacts with protonized 5-Br-PADAP to form a purple colored ion-association complex, having its absorption maxima at 580nm. The apparent molar absorptivity was found to be 1.1×10 5L·mol -1·cm -1, and Beer′s law was obeyed in the concentration range of 0～6.24μg of Cr 2O 2- 7 per ml of solution. The mole ratio of 5-Br-PADAP to Cr 2O 2- 7 was 1 to 1. The method described has been applied to the determination of chromium in some low alloy steel samples.

关 键 词：显色剂 测定 重铬酸根 吸光光度法 5-BR-PADAP 微量分析 合金钢 铬 

分 类 号：O614.411[理学—无机化学] O657.32[理学—化学]