5－Br－PADAP与钍的显色反应研究

Color Reation of Thorium with 2-(5-bromo2-pyridyazo)-5-diethylaminopheno

该文研究了５－Ｂｒ－ＰＡＤＡＰ在乙醇存在下与钍（Ⅳ）显色反应的适宜条件．实验结果证明在ｐＨ＝５．７０～６．１２范围内，钍（Ⅳ）与５－Ｂｒ－ＰＡＤＡＰ形成１：１深红色的配合物，其最大吸收峰位于５６４ｎｍ处．钍（Ⅳ）在０～２０μｇ／２５ｍＬ范围内符合比尔定律，由此计算其摩尔吸光系数ε＝４．３５×１０４Ｌ·ｍｏｌ（－１）·ｃｍ（－１），还对外来离子的干扰进行了研究，并进行了回收实验．

A sensitive spectrophotometric method has been developed for the determination of thorium with 2-(5-bromo-2-pyridyazo) 5-diethylaminophnol(5-Br-PADAP).The color reaction of this red complex is developed in the NaAc-HAc buffer solution at pH 5.82.Its molar absorptivity is 4.35×104L·mol-1.cm-1 at 564 nm,Beer's law is obeyed in the range of 0～20 μg Th (Ⅳ)/25 mL.The molar ratio of Th(Ⅳ) to 5-Br-PADAP in the complex has been estimated to be 1:1.The color of solution is stable for at least 50 min at the room temperature.