离子交换剂直接比色测定海水中微量镉与铬

近年来,在一般分光光度法—比色法的基础上,发展起来了一个新方法,使得比色法似乎在返老还童,又可与原子吸收、放化分析、极谱法竞相争雄了。这个新方法就是离子交换剂直接比色法1,2]这个方法的特点是(1)以半透明的离子交换剂为显色媒体直接进行光度测定;(2)离子交换剂能自稀溶液中富集待测成份,在一定条件下使待测成份在树脂上显色,之后不经过淋洗,即进行光度测定。这就把一般方法中“分离富集”和“光度测定”两步巧妙地合并成一步,结果使得本方法具有高灵敏度、简便快速等优点。但是,因为这一方法只是近年来才在文献上出现,所以在许多方面很不成熟,尚待不断改进和完善,特别是把此法应用到海水中微量元素的分析上,在文献上还未见有详细的和有效的研究结果报导。

Ion Exchanger Colprimetry in Direct Determination of Minor Elements in Sea water——Micro Determination of Cadmium and Chromium in Sea water

This article is a study of the new method of direct determination of minor cadmium and chromium in seawater by means of colorimetry,using reline of Chinese manufacture.The basis of this method is that ion exchanger is a translucent body,which enriehes in diluted solutions and can be subjected to direct spectrophotometric determination,under certain conditions,after colouring appears on it,making it unnecessary to get its eluate for examination.Experiments prove that as to systems with high distribution ration,their density as against the concentration of resinphase sample complex to be identified shows a straight line relationship,and similarly with their density against the primary concentration in liquid phase.This is the basis of the quantitative analysis of this new method,which is tens of times higher in sensitivity than the conventional colorimetry of liquide.Its ease of manipulation,elimination of the use of expensive instruments (e.g.in our experiments speotrophotometer type 721.of Chinese manufacture was used) and poisonous reagents makes it suitable for exteasive adoption with promising prospects,such as for enviromental analysis.