新显色剂对-二甲氨基偶氮氯膦的合成及其与钍显色反应的研究

Synthesis of the New Reagent of pDimethylaminochlorophosphonazo and Its Coloration Reaction with Thorium()

合成了新显色剂对－二甲氨基偶氮氯膦，研究了它与Ｔｈ（Ⅳ）的显色反应．结果表明：Ｔｈ（Ⅳ）在０～３０μｇ／２５ｍＬ范围内与该试剂形成的配合物在６７４，６１２和５３８ｎｍ３个波长处吸光度绝对值之和与溶液中Ｔｈ（Ⅳ）的浓度呈线性关系，故可利用该３个波长下吸光度绝对值叠加的方法测定Ｔｈ（Ⅳ），其ε值达１．７４×１０５Ｌ·ｍｏｌ－１·ｃｍ－１．由于显色反应在较强酸性介质中进行，本法有良好的选择性，大多数共存离子不干扰钍的测定，用于测定岩矿中的微量钍。

The synthesis of the new reagent pdimethylaminochlorophosphonazo(CPApDMA) and its colour reaction with thorium() were studied. In HCl medium, the reagent reacted with thorium() to form a blue complex with n nPApDMA]=12 and an apparent molar absorptivity of 986104 Lmol-1cm-1 at 674 nm. The accumulating method of absorbances at multiwavelength for determining thorium() was based on the sum of absorbances for the complex at 674, 612 and 538 nm, the apparent molar absorptivity in this case was \{174\}105 Lmol-1cm-1. Beers law is obeyed for thorium() in the range of 0￣30 g/25 mL. Most of the coexistent ions did not interfere with the determination of Th(). The method has been applied to the determination of trace amounts of thorium in rock standard samples with a high sensitivity and selectivity.