Dry Technique Extraction
|Note:||This technique is still experimental and may result in variable success if used with MHRB.|
Dry techniques (drytek) evolved from and are ideally intended for the implementation of the FASA method of crystallization and serve as the only techniques able to implement acetone as an extraction solvent. Acetone is generally favored for its ability to extract a notably broad range of active products.
- The use of dry techniques requires fewer and less toxic materials than the techniques that employ aqueous phases and separatory methods. The materials required are generally of a more household nature. They are most effectively applied to powdered botanical material. Acetone is, however, completely water miscible, so proper drying procedures are of the utmost importance. This technique may or may not require the defatting of botanical materials, depending on the intended method of crystallization. Dry techniques are the youngest of the current extraction techniques though apparently sound in theory and in practice.
Overview of Materials and Methods
- Acetone can be purchased at hardware stores but should be confirmed as pure acetone prior to purchase. Note that almost all acetone can contain up to 5% water contamination, depending on time and shelving conditions.
- In order to be utilized for extraction, sodium bicarbonate must undergo conversion to sodium carbonate.
- Lime is often found difficult to decant acetone off of and also difficult to filter out of acetone, whereas sodium carbonate is generally found more agreeable for both.
- Distilled water is preferable, as tap water almost always contains impurities that can potentially tamper with resulting yields.
- With few exceptions, the source material should be completely pulverized to a powder consistency before use, as this technique's choice of reagents are not quite capable of penetrating cell structure.
- Extractions by dry techniques are characterized by the lack of a traditional aqueous phase in the extraction process, and instead, opting for basification within a paste which is followed by chemically drying the paste with desiccant. The process does not make use of separatory methods, and instead is characterized by it's use of dry-washing, decanting and non-intensive filtering methods. Certain materials must be rendered anhydrous prior to use.
- Mix the intended base with the powdered source material at a ratio between 1:2 and 1:1.
- The product remains in its natural salt form which is generally considered to be quite free from the botanical cell structure in powdered material.
- Add only enough water to thoroughly moisten the mixture to the consistency of a paste while stirring to ensure the consistency of the mixture.
- Although this is not generally considered a traditional aqueous phase in that it is not a solution, it is an aqueous phase in that it is excessively hydrated and sufficiently aqueous to facilitate reaction.
- Allow adequate time to soak in order for reaction to occur.
- The acid component of salt-form product undergoes reaction with the base, effectively neutralizing the acid and freeing the product in its pure alkaloid form, or freebase.
- Stir in anhydrous magnesium sulfate until thoroughly dry.
- The magnesium sulfate acts as a desiccant, and that this is performed in order to prevent water contamination of the acetone.
- Add an excess of anhydrous acetone and stir thoroughly, allotting adequate time and stirring for thorough dissolution of the product into the acetone.
- The more contact allotted between the product and the acetone, the greater the saturation.
- Decant and/or filter acetone and collect, being careful not to allow any particulates into the collection vessel.
- The bases used should not harm the quality of the product, but may interfere with the accuracy of weight.
- Repeat steps 5-6 with fresh acetone until material is exhausted to satisfaction.
- Three washes is generally considered sufficient.