Plant Polyphenols Fatong Leaves The Measurement And Extraction Research

The determination of plant polyphenols exist in phoenix tree leaves is discussed in this thesis. In addition, some researches on its extraction and analysis are done.Using tartaric acid sub-iron colorimetry and Folin-Ciocalteu reagent colorimetry respectively, the content of the plant polyphenols is determined. The best determination condition based on tartaric acid sub-iron colorimetry is as follows: sample particle size is 0.45mm; extraction temperature is 80°C; extraction time is 45 minutes; the solution pH value is 7.5; the dosage of tartaric acid sub-iron is 5mL. Under the above condition, the content of plant polyphenols is 2.11% by using this method. Using the Folin-Ciocalteu reagent colorimetry to do the same research, the content of plant polyphenols is 2.19% under the following best determination condition: sample particle size is 0.45mm; extraction temperature is 70 °C; extraction time is 25 minutes; the pH value of the solution is 11; the dosage of Folin-Ciocalteu reagent is 5mL. The two determination methods are good according to the relativity comparison.The condition of extraction using iron sedimentation method is optimized, and the best extraction condition is as follows: the concentration of ethanol is 40%; proportion of material and impregnant is 1:10; extraction time is 40 minutes; extraction temperature is 80 °C. Al³⁺ and Zn²⁺ are chosen to be precipitator which is used for sedimentation of plant polyphenols and the influence resulted by the dosage of the precipitator, the acidity of the liquor and the sedimentation time as well are investigated. The best sedimentation condition is as follows: the dosage of precipitator is 0.3g; the pH value of the liquor is about 6; the time for sedimentation is 30 minutes. Ethyl acetate is chosen to be extraction solvent to extract plant polyphenols after which are dissolved by hydrochloric acid. By vacuum dryness, the output of the plant polyphenols is 0.229g that is about 1.15% of the weight of the leaves. By using tartaric acid sub-iron colorimetry analysis, the purity is 95.1%.