Gingko Flavonoid is the Ginkgo biloba extract. It can increase CBF and improve the function of cerebral circulation. It also can protect brain cells, expand coronary artery, prevent angina and myocardial infarction, prevent thrombosis, and enhance the body's immune ability. It’s good for the patients with coronary heart disease, angina pectoris, cerebral arteriosclerosis, senile dementia and hypertension. The methods of determination are derivatives-gas chromatography, reversed-phase high performance liquid chromatography (HPLC), colorimetric method and so on.

 

This article mainly introduces a new method-spectrophotometry. Spectrophotometry is determining absorbance of light or luminous intensity of the material tested at a particular wavelength or within a certain wavelength range to make the qualitative and quantitative analysis of the material. The method is based on gingko flavonoids reacting with sodium tungstate to generate yellow tungsten acid ester. This method is highly sensitive, simple, fast, and reliable. If it can be used for the determination of actual samples, a satisfactory result will be got.

Experimental Methods:

1. Respectively add 0.08 mol/L sodium tungstate solution 2 ml in two 25 ml colorimetric tube. Add a certain volume of gingko flavonoids standard using liquid and shake well to dilute to scale.

2. Another is added to scale directly. Put the former in sample pool, the latter in reference pool and determine its absorbance at 304 nm.

Experimental results:

1. The reaction product of tungsten acid ester has maximum absorption at 304 nm, so the experiment selects the wavelength as measuring wavelength.

2. The acidity of the solution has a big influence on the production of tungsten acid ester, so the experiment selects neutral conditions to reaction.

3. The amount of sodium tungstate has a certain influence on the formation of tungsten acid ester. With the increase of the dosage of sodium tungstate solution, absorbance also increases accordingly.

4. At 20 ℃, absorbance value of solution is maximum. 40 minutes later the absorbance value decreases gradually.

5. The linear range of the method is 4 ~ 120 mu g/ml. Through determining of samples, the recovery is 100.0% ~ 100.6%.

 

In conclusion, the spectrophotometry of rapidly determining gingko flavonoids in pharmaceutical preparations has the advantages of convenience, rapidness, wide linear range, high sensitivity, high accuracy, less reagent dosage, less interference and good reproducibility. It can be easily used in determining gingko flavonoids in pharmaceutical preparations.