107. Solving a chemistry problem

In the preparation "Digitoxin" (FS 42-2415-85), calculate the specific absorption rate: about 0.02 g of the preparation (accurately weighed), dried at a temperature of 100 - 105 ° C, is dissolved in 95% ethanol in a volumetric flask with a capacity of 50 ml. Place 5 ml of this solution in a 50 ml volumetric flask and make up to the mark with 95% ethanol. To 5 ml of the resulting solution add 5 ml of sodium picrate solution, incubated for 20 minutes at room temperature. The optical density of the resulting solution at a wavelength of 495 nm and a layer thickness of 10 mm is 0.880;