[Content Detection] Total Flavones
The Preparation of Reference Sample Solution: Weigh accurately 20mg reference sample of Rutin in a 50ml volumetric flask. Add some amount of 60% Ethanol and heat over a water bath to dissolve. When it becomes cold, add 60% Ethanol to the mark, then shake well. Measure out 25ml of the solution accurately, put in a 50ml volumetric flask, add water to dilute to the mark, shake well. (0.2mg Rutin per 1ml solution)
The Preparation of the Standard Curve: Measure out accurately 1ml, 2ml, 3ml, 4ml, 5ml, 6ml of the reference sample solution and put in a 25ml volumetric flask separately. Add 6.0ml of the 30% Ethanol and 1ml of the 5% Sodium Nitrite solution to each flask, shake well. Put for 6min, then add 1ml of 10% Aluminium Nitrate Solution to each flask, shake well, put for 6min again. Add Sodium Hydroxide test solution 10ml, and then add 30% Ethanol to the mark, shake well, put out for 15min. Use the same reagent blank as the reference, through UV-Vis Spectrophotometry to absorb the absorbance at 500nm. Draw the standard curve with absorbance as the ordinate and concentration as the abscissa.
Detection method: Accurately take the crude sample powder around 2g, add 60% Ethanol to 30ml, heating reflux for 2 times, cool down, filtration. Add 25ml of 60% Ethanol to the residue, heating reflux for 2 times, each time for 1 hour, filtration. Combine the two filter solution and put in a 100ml volumetric flask. Use 60% Ethanol to wash the residue, and combine the washed solution to the same flask, shake well. Accurately measure 25ml in a 50ml volumetric flask, add water to the scale, shake well, and take this as the testing solution. Accurately measure 3ml of the testing solution, put in a 25ml flask, add 30% Ethanol to 6ml, refer to the preparation of standard curve method, from the “add 1ml of Sodium Nitrite solution”, determine the absorbance. Meanwhile, take 3ml of the testing solution, do the same steps as above except from adding the Sodium hydroxide solution. Use the same reagent blank as the reference, read the weight of rutin in the testing solution from the standard curve (mg), calculation and get the result.
This item is calculated base on dry basis, and detect the total flavones content as Rutin (C27H30O16) of which not less than 1.5%.