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This year licensed pharmacist Chinese medicine chemistry knowledge: separation and purification methods

2018-05-10 01:36:31

The following is the knowledge point of TCM chemistry of licensed pharmacists: separation and purification methods, not written completely, I hope everyone can get a good result

Methods/Steps
1

Simple extraction method In the systematic study of Chinese medicine components, the usual method is to concentrate the water extract of Chinese medicine appropriately, or concentrate the ethanol (methanol) extract of Chinese medicine appropriately, after recovering the alcohol, add an appropriate amount of water, use organic solvents with different polarities that are not miscible with water, and the polarity goes from small to large. For example, the selection of petroleum ether (or hexane), chloroform (or ether), ethyl acetate, n-butanol, respectively extraction, respectively recovery of solvents to obtain extract with different polarity. In some cases, only 1 or 2 solvents can be selected for extraction.

2

Continuous extraction method In order to overcome the operation trouble of multiple extraction using a liquid separation funnel, a continuous extractor can be used. This instrument takes advantage of the fact that mass transfer occurs when naturally stratified and dispersed phase droplets pass through continuous phase solvents with different specific gravity of the two solvents. When selecting the continuous extraction method, it is necessary to use different types of instruments depending on the specific gravity of the solvent used is greater than or less than the specific gravity of the aqueous solution to be extracted.

3

Precipitation method is a method in which the separated substance is dissolved in a solvent, and then another solvent or reagent is added to precipitate some or some components, and some components are retained in the solution after filtration to achieve separation. The impurities can be precipitated, and the desired components can be precipitated.

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