【摘要】 <正> 偶氮氯膦—mN(简称—mN)是一种新型稀土显色剂,用其测定稀土总量及铈组分量已有报道。但用试剂进行钍的光度测定未见报道。本文研究了钍—mN络合物的形成条件及其应用于光度分析中的可能性。实验证明,钍与mN络合物在硝酸-磷酸-草酸介质中,形成稳定的络合物,且具有发色快,灵敏度高于偶氮胂—Ⅲ,稳定时间长,温度影响小,对比度大,工作曲线线性范围宽等特点。更多还原

【Abstract】 A new spectrophotometric method for the determination of Th was investigated, using Chloro-Phosphor-azo mN as colorific and Complexing Agent. The optimum conditions, such as the amount of the reagents added, the suitable tempearature, and the stability of the complex were found. λ_max of the complex is at 665nm. The best medium for Th（Ⅳ） is 25ml analyzed solution containing 0.03% mN 4ml, 1NHNO₃ 2ml, 1:1 H₃PO 1ml and 10% H₂C₂O₄ 4ml. The complex compound is stable for 27 hours at 11—45℃. In 25 ml solution, 0—55μg Th （Ⅳ） obey’s Beer’s law. ε=7.8×10⁴ liter/Mole·cm, s=2.79×10³μg/cm². By means of Mole-ratio Method and Successive Variation Method, the ratio of Th: mN in the complex compound was proved to be 1:6. The proposed method was applied to the analysis of Rare earth ore for the determination of micro-amount of Th. Th （Ⅳ） in sample solution was separated from Rare earth, Fe, Ca and Ti by means of Paperchromatographic Method, using ascending process for 4 hours with Whatman No. 4 chromatographic paper. Mixture of n-butyl alcohol, methyl-iso-butyl ketone, butyl ketone and nitric acid in the ratio of 20:45:45:50 was used as developing agent. A good separation was obtained. The recovery factor of Th was proved experimentally to be≥98.5%. After separation, Th was brought into solution and determined with the new method. Many samples of two different ores were analyzed, the results obtained were satisfactory. Standard deviations were 0.3% and 0.5%; variation coefficients were 1.5% and 1.9% respectively.更多还原