抄録
Application of solvent extraction to the polarographic method of analysis is reviewed. In the polarographic method of analysis, in general, the interference of other elements which do not concern to the analysis is avoided in the way of selecting suitable electrolytes, appling .A.C. polarographic method and so on. There are, however, a few cases in which these procedures are not enough to get fine steps in waves. In such cases chemical seperation method must be applied. For the chemical separation method, the solvent extraction is a good one, especially of its high selectivity and its quickness. And combining this solvent extraction and the polarographic method in suitable ways, the extent of the polarographic method of analysis becomes much wider. Solvent extraction may be classified into chetate-and ion association-extraction. Tne former is used mainly for the separation and condensation procedure of elements which are to be determined, for the amount of metal extracted by this method is limited to low degree. The typical solvents for it are dithizone, cupferron and so on, which can be easily decomposed. On the contrary, in the latter, ion association system, a large amount of metal can be extracted, so that it can be applied not only to condensation of trace components but also to removal of principal components, thus it has a large extent of application. For instance, iron is separated and removed away from hydrochloric acid solution by ether extraction, while, in order to determine impurities in indium metal, indium is extracted from hydrobromic acid solution and removed out of the system. For other examples, to determine zinc in cadmium and tin in lead cadmium and zinc are extracted from thiocyanic acid solutions. Recently, amines having hlgn molecular weignn-a liquid anion cxchanger-are marked as a new type of extracting solvents. Extraction procedure with them will be utilized broadly in the case of determination of zinc in copper and in uranium, indium in cadmium and so on. As being applied to the determination of uranium, it seems a very interesting method to determine metal quantities in non-aqueous solution by polarograph. The procedures are as follows; metals are extracted to organic phase and the solution containing metals is diluted with other organic solvent of high polarity. And then, the metals are determined with the polarographic method in this diluted non-aqueous medium. (translated by S. Shibabe)
