A MICRO DETERMINATION METHOD FOR SYSTEMATIC ANALYSIS OF METALS BY THE RING OVEN TECHNIQUE COMBINED WITH SOLVENT EXTRACTION AND ITS APPLICATION TO INDUSTRIAL HYGIENE

A systematic method for micro semi-quantitative determination of mixed metals has been developed as a combined technique of the Weisz's ring oven and the liquid extraction methods which is availabole to the conventional and rapid measurement for the hygienic purposes. By this technique the metal in question in the test solution is extracted with organic solvents, which dissolve the element specifically by ion association or chelate formation recation, and after separation from the other elements coexisting in the test solution the element is recovered in a shape of a thin solid ring (15∼43 mm diameter) on a filter paper put on a ring oven apparatus. The semi-quantitave analysis was done by contrasting the stndard colour series previously prepared with the series of sample solutions at known concentration levels. The higher sensitivity in detecting the trace of metal with less contamination by the other coexisting elements on the procedure and the increased rapidity in the determination have been realized by the use of the solvent extraction rather than the use of inorganic separating reagents in the analytical procedure. Basic analytical experiments were carried out in order to assess the rate of separability of the respective element from the others at several amounts of constituent, and the sensitivity in detection of each element. Out of test solutions containing metal fumes taken from the environmental atmosphere in the working fields, Fe-Ni-Cr and Sb-Sn-Cu-Pb components as most popular examples of metal fume mixture, were determined semi-quantitavively with selected combination of separating solvents and colour reagents in order to attain the most sensitive and precise systematic separation procedures of each element.