Abstract
1) As a color reagent for santonin, 2, 4-dinitrophenylhydrazone, 1% pure alcoholic solution of sodium hydroxide was used instead of 1% aqueous solution of sodium hydroxide used in the previous method. A reddish purple color appeared when the reagent was added to the acetone solution of the hydrazone and the light absorbency (e) of the colored solution of different concentrations (γ) was measured by the Beckman spectro-photometer (λ=550mμ). From these experimental data (n=18), the following equation was calculated by the method of least squares: γ=1365e+6.51.
2) The standard deviation, σ, is 0.0168, and the concentration limit corresponding to 2σ limit is ±57.3γ.
3) Results obtained from the determination of pure santonin by this method agreed with the expected values.
4) The influence of bisatin on this method was found to be negligible.
5) Test conditions were found for colorimetric assay of santonin using 1g. of crude drug (Artemisia maritima).
6) Data obtained by the baryta method, 2, 4-dinitrophenylhydrazone gravimetric method, and the present colorimetric method were compared.
