The chemical components contained in natural medicines are relatively complex, and for natural medicines of unknown composition, before extracting and separating their active ingredients, we should first understand what types of chemical components may be contained in them, which requires a relatively simple and rapid qualitative method to understand the situation of the components contained in them. Then, according to the nature of the contained components, design a suitable extraction and separation method, in order to provide a certain reference for separating the active ingredients as completely as possible.
Operation method
Isataka Yamaguchi's law
Principle
There are many systematic pre-test methods, mainly including the following: 1. Yamaguchi Ichitaka method This method is in accordance with the lipophilicity and hydrophilicity of the plant components, acidic and alkaline, volatile and non-volatile into several parts for pre-testing. 2. Increasing polarity solvent method This method is based on the difference in the degree of lipophilicity of the components of the Chinese herbal medicine, the use of a variety of solvents with different polarity, extraction, so that it is divided into a number of parts. 3. General extraction solvents according to the polarity of the size of the petroleum ether, trichloromethane, ethyl acetate, acetone, n-butanol, etc. 3. Other methods In addition to the above methods, can also be used to simplify the extraction method, to the total extract for pre-test. For example, aqueous extract can be used for pre-testing of sugars, polysaccharides, organic acids, saponins, phenolics, tannins, etc.; ethanol extract can be used for pre-testing of flavonoids, anthraquinones, glycosides, organic acids, coumarins, terpenes and lactones, sterols, etc.; and acidic alcohol extract can be used for pre-testing of alkaloids. Move I. Identification of Alkaloids: HANPROFENSE 1. Preparation of test solution For more product details, please visit Aladdin Scientific website.
Take about 2 g of crushed herb, add 20~30 ml of distilled water and add a few drops of hydrochloric acid to make it acidic. Heat at 60 ℃ on a water bath for 15 minutes, filter, the filtrate for the following tests.
2. Identification of alkaloids
Alkaloids (with a few exceptions) are associated with a variety of alkaloid precipitation reagents in an acidic solution (aqueous or dilute alcohol) to produce a precipitation reaction. The operation is as follows:
Take about 1 ml of the above prepared acidic aqueous solution and add drops of bismuth potassium iodide reagent (Dragendorff's reagent). If there is a precipitation reaction, it indicates that the sample may contain alkaloids; observe the color of the precipitate.
Predict that this sample contains alkaloids The following experiments are optional after school 1). Mercury potassium iodide reagent (Mayer's reagent): acidic aqueous extract is added dropwise with mercury potassium iodide reagent to produce a white precipitate. 2)． Iodine-potassium iodide reagent (Wagner's reagent): acid aqueous extract is added dropwise with iodine-potassium iodide reagent to produce a brown precipitate. 3)． Silicotungstic acid reagent: Acid-water extract dropwise addition of silicotungstic acid reagent produces a light yellow or off-white precipitate. The acid aqueous extract reacts with all (or most) of the above four reagents to produce a precipitate, the Alkali.