Abstract
The method is based on the same principles as one for digitalis recently reported by us. 1 It is a colorimetric method making use of Baljet's 2 reaction, which takes place between the active principles of strophanthus and dilute alkaline picrate solution, giving an orange red color.
The method consists of first decolorizing the tincture, or other solutions of strophanthus, with lead acetate and then removing excess lead acetate with sodium phosphate. The decolorized solution is then treated with an alkaline picrate solution; the characteristic color develops in 20 minutes. As a standard for comparison a Ouabain solution is used in which the color is developed in a similar manner.
In the table below are given the results of this method compared with those by the Hatcher and Brody 3 cat bioassay method. It will be seen that the agreement between these two methods is very close. The chemical method permits of a direct determination of the amounts of strophanthin.
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