The quick method described earlier is by far the simplest way to isolate salvinorin A as crystals. If you have some blackwax, or an overnight extract which you wish to purify, then 'flash' column chromatography is required.
The method described here , is done using a pasteur pipette as the column. It is only suitable for extracts of upto 3 so grammes of dry salvia leaves. It is the best way to hone your skills without wasting much material. Once mastered, you can scale it up and use large columns.
The following materials are required.
Good quality Naphtha, Ethyl Acetate, Acetone
Chromatography grade silica.
Pasteur pipettes, stand for pipette, some vials, air-tight jar,cotton wool.
Warning: avoid breathing silica powder.
Step 1. Drying of the silica
Later we will make the silica less tenacious, by adding some water to it, but initially it must be dried from any adsorbed water, to enable us to know its real weight. So, put 10g or so of the silica in a bowl and heat in a 110 C pre-heated oven for an hour.
Remove from oven, and using a funnel or paper, transfer to a clean, air-tight jar and screw the top.
Step 2. Deactivating the silica.
The dry silica is too strong for our purpose and it must be deactivated by spraying with water. 15% water is added in our case.
Weigh the silica and place on a flat plate. Calculate 15% of the weight. (eg say it weighed 10g, then 10x0.15=1.5g) Use a spray bottle to spray the weight of water (1.5g in the previous example) onto the silica. This is best done with a few squirts, mixing and spreading the silica inbetween, to acieve uniform wetting.
Step 3. Filling the Pasteur pipette with silica.
Insetr a small plug of cotton in the pipette and push it down until it bottoms with a stick. Add some of the deactivated silica to the pipette, until half is filled. Tap the side to settle the fine powder.
Step 4. Adsorbing the crude extract on silica.
In this step we 'transfer' the extract onto a little silica, which will be added to the top of the silica in the pipette. Dissolve the blackwax (no more than 50mg) in as little acetone possible. Now, place a little (1/4 inch square) of silica on a little spoon and gradually add drop by drop, some of the acetone solution. Stop when the silica is soaked, and aloow to dry by blowing on it. When it can take more, add more drops. Repeat until all of the acetone solution has been used.
Imortant. Make sure all of the acetone has evaporated before going to the next step or you will be wasting your time.
Step 5. Use a spatula or similar to powerder the small quantity of silica in step 4. Use a small piece of paper to transfer the green silica to the pasteur pipette. You will now have a green band above the white silica. Plug with a littl cotton wool pushed down onto the top surface of the green silica.
Step 6. Eluting Place the pipette in a stand. Put a vial under neath. Now add pure naphtha until it is at the top. Using a pipette teat, or a ruber tube to your mouth, create a little pressure, forcing the liquid down. When the the to of the liquid reaches the cotton above the green silica, stop. Add another lot of naphtha and repeat.
You will see a yellow band, separating from the green silica.
Now make (or make before!) some 15% ethyl acetate (EtOAc) in naphtha (for 5 ml, mix 0.75ml EtOAc with 4.25ml naphtha). Repeat the above .
The vial at the bottom will now contain the yellow rubbish (not salvinorin).
Change the vial if desired, and repeat with 2 lots of 30% EtOAc. A dull green substance is eluted. Change vial and repeat with 40% EtOAc. This time a bright green substance elutes. You will notice a yellow band almost eluting. The salvinorin A elutes with this yellow substance. Change vial and elute with 60% EtOAc. Keep the yellow solution and evaporate off the solvent.
Congratulations, you have purified the black crap to a much purer mixture.
Practice and master the method, and only then move to a larger scale. Initially it may seem like a difficult method, but it really is easy, once mastered.
