利用新的指示反应催化光度测定痕量银

The Photometric Determination of Trace Silver by Catalytic Method with a New Indicator Reaction

催化动力学分析法测定痕量银的报导相对较少,至今仅二十多篇[1-4],其中大多数是以过硫酸盐作氧化剂。用H_(2)O_(2)作氧化剂的体系文献报导很少[5]。本文在实验基础上,发现在Na_(3)PO_(4)-Na_(2)PO_(4)介质中,银能催化H_(2)O_(2)氧化硫酸对氨基二乙基苯胺,得紫红色产物,其颜色随时间延长而加深,反应速度在一定范围内随银用量增大而加速。本文研究了一系列反应条件之后,拟定出了催化光度测定痕量银的分析方法。

Suitable conditions for the determination of trace silver by using a new indicator reaction on the basis of the oxidation of p-amino-N,N-diethylaniline sulphate with hydrogen peroxide catalyzed by silver itself are studied in this article.The apparent activation energies of the catalytic and uncatalytic reactions were calculated.The method has been applied to the determination of silver in various geological samples with satisfactory results after separation by extraction with dithizone.