偶氮砷三號(Arsenazo-Ⅲ)為比色劑之分光光度定量各水試樣中微克釷 作者:許明星

摘要：

藉偶氮砷三號（Arsenazo-III）為比色劑，分光光度法定量各水試樣中微克釷，業經研究。
一、當釷對諸元素之比率不超過：比100（正一價，正二價陽離子）；1比30（稀土和正三價陽離子）；1比2（UO₂⁺²,Zr⁺⁴）時，分光光度法能直接定量如後：加1.5ml 10%抗壞血病酸（Ascorbic acid）溶液和1.5ml 10%氯化氫（合）羥胺（Hydroxylamine hydrochloride）溶液入試樣中，煮沸，待冷卻至23～25℃，混合0.5ml 0.1% Arsenazo-III比色劑溶液，用水稀釋至10ml，調至pH 0.5，由紅色濾光器，在665mμ測定之。每含04～28微Berr克釷之全程系試樣，符合律。
二、試樣在任何超過上述量之陽離子或1 ml 0.1M之任一F-，SO₄^-2，SiO₃^-2，NO₃-之陰離子存在下，得以包括加1m1之62%HCIO₄蒸煙和Fe(OH)₃，為載體沈澱二次之手續(a)有效分離而測定之。至於大量之UO₃⁺²，U⁺⁴，Zr⁺⁴，Ti⁺⁴，與其選手續(a)毋寧採用CaC₂O₄為載體之手續(b)。
上述諸手續測定釷誤差，均少於2.5%。

《詳全文》

Spectrophotometric Determination of Microgram Quantities of Thorium in Various Aqueous Samples using Arsenazo-III Author: Ming-Sing Hsu

Abstract：

The spectrophotometric determination of microgram quantities of thorium in various aqueous samples using Arsenazo-III as reagent was studied.
I. When the ratio of thorium to elements is not in excess of: 1 to 100(1+,2+ charged cations); 1 to 30(rare earth and 3+ charged cations); 1 to 2 (UO₂⁺²,Zr⁺⁴), they can be determined directly by spectrophotometry as follows: Add 1.5ml of 10% solu'n of ascorbic acid and 1.5ml of 10% solu'n of hydroxylamine hydrochloride to the sample, boil, cool to 23-25℃, mix with 0.5ml of 0.1% solu'n of Arsenazo-III reagent, dil, to 10ml with water, adjust to pII 0.5, and measure at 665mμ with a red filter. The system conforms Beer's law over the range of 0.4-28 r Th per sample.
II. In the presence of the quantites of any cations exceed the above statement or 1 ml 0.1M of any anions of F-, SO₄^-2, NO₃- , SiO₃^-2, the samples can be separated and determined effectively by procedure (a) which consists of adding 1 ml of 62% HCIO₄ to be fumed and precipitating twice with Fe(OH)₃ as carrier. As for great quantities of UO₃⁺²，U⁺⁴，Zr⁺⁴，Ti⁺⁴，procedure (b) using CaC₂O₄ as carrier is preferred to procedure (a)
The estn. Error in Th is less than 2.5% in all the above procedures.