Extraction of arsenic, mercury, gold, silver, antimony, indium, bismuth, tellurium, cadmium, zink and copper iodides with methylisobutylketone was examined in the sulfuric acid of concentrations from 0 to 15 normalities. Although, arsenic and zink iodides were extracted from 6 to 12 normalities, extraction of other metal-iodides were carried out in more wide range of sulfuric acid concentrations almost from 2 to 12 normalities. Iron, sodium, potassium, magnesium and calcium iodides, these, being chief biological elements of inorganic substances, were not extracted in the least into methylisobutylketone layer from sulfuric acid solution. Copper and zink were normal elements of biological materials and were extracted into methylisobutylketone layer by this procedures. The flame interferences of copper and zink were not recognized in determinations of gold, silver, antimony, indium, bismuth, tellurium and cadmium. To investigate the influences of biological elements, mock solutions of human blood and urine were prepared. The addition of mock blood does not excessively interfere with determinations of arsenic, mercuy, indium, bismuth, tellurium, cadmium, silver and antimony with the exception of gold. However, with addition of mock urine negative interferences were strongly seen in antimony determination, while in mercury, indium and silver determinations only slight interferences were observed. To examine the influences of sample preparation techniques, gold, silver, indium, cadmium and copper were treated both by wet ashing (nitric acid and sulfuric acid) and dry ashing. The recovery rates of such metals were almost above 90%, but in the treatment of dry ashing of gold only less than 60% was recovered. This procedure, in which only potassium iodides was added to sulfuric acid solution after the treatment of wet ashing and extracted with methylisobutylketone, is very simple and easy compared with chylating reagent method. Therefore, the minimum contamination from reagents and practices is expected.
