0731. Solving a chemistry problem

1. Calculate the percentage of vinpocetine in vinpocetine tablets from the declared amount of vinpocetine, if a sample of powdered tablets weighing 0.0101 g was dissolved in a 50 ml volumetric flask. 5.0 ml of the resulting solution was placed in a 25 ml volumetric flask and the volume of the solution was adjusted to the mark with 96% alcohol. The optical density of the resulting solution was 0.603 at 314 nm in a cuvette with a layer thickness of 10 mm. The optical density of the vinpocetine standard sample solution was 0.621 in a cuvette with a layer thickness of 10 mm, the concentration of the vinpocetine standard sample solution was 0.02 mg/ml. The declared content of vinpocetine per tablet is 5 mg, the average tablet weight is 10.2 mg.