Alkaloid Extraction

The method I use is a general one - I copied it from one used by some scientists to extract mescaline from peyote, but I have since seen close variations used on many plants. This procedure is followed whenever a plant is studied for its alkaloids.

A few ingredients and bits of equipment are necessary. I am a chemist, and have my own chemistry set. I have considered manufacture, but I find that there are enough interesting things to do just extracting natural compounds, which is much easier, indeed, possible in the home.

You will need:

As far as a still goes it is to recover solvent, and leave goodness as a residue at the bottom. I use a bit of quickfit I nicked: a round bottom flask, short column, thermometer on top, and a small condenser... takes forever, but don't expect to follow this procedure in anything under a day.

Other bits and pieces:

A filtre of some sort is a necessity; preferably a good one, with a vacuum pump if you are filtring gluggy stuff (cactus is the worst, sticky goo, e.g., other things like seeds and bark are better). People have been known to use such devices as coffee filtres, t-shirts, tins with holes in the bottom (as a filtre press) and so on. Whatever you can scrounge. A lab buchner funnel, sidearm flask, and venturi pump are ideal. All this stuff is standard in any chemical lab, regardless of discipline.

Chemicals necessary:

The idea is this: Most fun compounds (the only exception is maybe THC, and alcohol if you count that) are basic - they contain nitrogen. So: in general, if you react them with hydrochloric acid, they form a water soluble chloride. If you react them with dilute base in the aqueous phase, they go back to being a base, which is insoluble in water, but soluble in organic non-polar solvents (like CH2Cl2). So, the theory is, that only a base will go from water to solvent and back to water etc. when changed from acidic to basic and back to acidic. This gives you a way of removing all the other crap which is not alkaloid from a sample. That is the theory. When I do this, if I can get down to some brown or green sludge that I can throw down or smoke, I am happy with a good days work. Ideally, you should end up with lovely white crystals, but I think that would require a lot of time and effort, and indeed a considerable loss of product in the process.

Procedure:

Now, depending on what your stuff is, you have to let the methanol have time to remove it all. This is best done by leaving in a quiet warm place for a few days, even up to a week, and shaking it occasionally so it is mixed. Some papers recommend solvent extraction (soxhlet apparatus) and refluxing at the boiling point of the methanol (80 degs or so - I can't remember). I usually just rely on time to get the good stuff out. When you are ready (early in the morning), filtre the muck, to give you methanol+dissolved brown gunk, and a residue soaked with methanol. The residue still contains a lot of good stuff, so soak again for an hour, and repeat, and do a third time if you are feeling generous (3 is the magic number in extraction work).

When you are done, there is another thing you can do finally, if desired: depending on what your stuff is, mix it up with dilute hydrochloric acid, 1M is appropriate. let stand for an hour, then filtre (this may be very difficult) That will get the last of the alkaloids out of the substrate.

You now have a methanol-plant stuff mixture, and a dilute HCL-plant stuff mixture, if you bothered to do that part.

Evaporate the methanol, to leave a small amount of goo. This will contain water, a bit of methanol, and all kinds of resins and muck, and if you are lucky, the alkaloids.

If a very quick and crude extraction was all that was desired, then after stripping the last of the methanol with vacuum if possible, this residue could be smoked, eaten or whathaveyou. I leave that to your discretion. However, if a cleaner product is desired, the double layer extraction will need to be performed.

Combine the evaporated methanol gunge with the hydrochloric acid filtrate if you have any. If you don't then mix the methanol stuff with an excess of dilute (1M) HCl. Feel free to filtre again at this point. Anything of marginal solubility here is no good to you. Get the stuff as clean as possible. Boiling with activated charcoal is another useful trick for removing gunge. Just boil it up, and filter off the charcoal for a cleaner brew.

You should now have an acid aqueous solution of alkaloids and water solubles from the plant.

Take your acidic solution, and basify. This is done by mixing in dilute sodium hydroxide (I use up to 5M to save on total volume. Be careful with concentrated NaOH - apart from eating skin, it eats alkaloids) As you mix in the NaOH, you will see swirls of white precipitate form and redissolve. Continue until the white swirls stay, and until the solution is quite cloudy. Indicator paper is necessary to see that the solution is basic. If you can't get indicator paper, you can make an indicator by boiling up some purple flowers. The dyes in most flowers go bright red in acid, and green in strong alkali. Just a drop of dye and a drop of mixture should tell you what is acid or base.

The white precipitate is the alkaloids. The more the better.

Next, add equal volume of non-polar solvent (dichloromethane) to the mix. Place in separating funnel, and shake. Separate. This may be very difficult or slow. Adding more solvent, more basic water, etc. may help. Adding lots of salt to the water layer will help break an emulsion. Ideally you want to do this step 3 times - to extract as much as possible from the water layer into the organic. I find this part very difficult, and you have to accept that you will lose quite a lot of material here. It is, however probably easier with some plants that others: cactus is very difficult, barks and seeds would be easier. Use plenty of salt, and agitate to separate.

When you have finished extraction, chuck the basic water layer. The solvent layer is kept, and can be backwashed with salty water for a cleaner mixture.

The solvent can now be dried, (using salt or some dry powder, the filtred) (I don't usually bother with this - the old hairdryer at the end can remove some last solvent and water) then strip the solvent in a vacuum to get your final product - some kind of syrup could be expected. This is super concentrated, but may only be half the strength of the original. e.g. put in enough for 10 doses of morning glory seeds, get back 5 doses or more of concentrated alkaloids.

If it is desired to take the process still further, you can do the obvious thing - mix your solvent layer with dilute acid again and extract back into water. Acid layer could be evaporated under vacuum to give salts of alkaloids. Alternatively, if the organic layer were scrupulously dry, bases could be salted out with some organic acid - a tartrate, oxalate could be formed. I have never bothered with such things - you would need a lot of pure extract to be bothered. The acid-base extraction process can be continued as many times as is desired.

If a truly pure product is desired, the only way to go from here is chromatography. I have never used this at home, and wouldn't think it was worth the trouble, but there will be papers available on what was used for a particular extraction case.


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