For some time past this writer has been interested in the potassium content of muscle. When this interest was first aroused he became aware of the need for a satisfactory method for determining quantitatively the amounts of potassium in a given muscle. So there ensued a search of the literature. This yielded three fundamental methods, each of which had its advantages and disadvantages. The Perchlorate and the Chloroplatinate methods were not used because of the technical difficulties presented by them. Jacobs and Hoffman (1931) had used the Cobaltinitrite methods with muscle and had obtained good results. So their method was used for the problem at hand. This method required that the material to be analysed was ashed for several hours in a muffle furnace at extremely high temperatures to destroy the organic material. The ash that was left was then dissolved in distilled water. To this solution of ash then was added an excess of the sodium cobaltinitrite reagent. The resulting solution was allowed to stand five minutes and then centrifuged for 15 minutes. The supernatant fluid was then discarded and the precipitate was washed with a few c.c.'s of 70% alcohol. Then the ash was redissolved in 2 ml. of boiling water and allowed to cool. To it was added the 2 c.c.'s of 1% chlorine chloride solution and 2 c.c.'s of 2% sodium ferrocyanide solution. This solution was then diluted to 6 c.c.'s with distilled water. If there was potassium present the solution turned green immediately and the depth of this green color is proportional to the concentration of the potassium. The color of the solution was then compared with a standard potassium solution in a colorimeter.
Proceedings of the Iowa Academy of Science
©1952 Iowa Academy of Science, Inc.
Aronson, Joab Klapp
"A Simpler Quantitative Method for the Determination of Potassium in Tissues,"
Proceedings of the Iowa Academy of Science, 59(1), 402-403.
Available at: https://scholarworks.uni.edu/pias/vol59/iss1/57