Column chromatography for honey oil

Does anyone have experience using column chromatography for the isolation of cannabinoids (mainly THC) in honey oil? I've researched high and low and have only been able to find mentions but nothing helpful for someone figuring it out. My basic idea was to run ground bud through a Soxhlet with hexane, purify through silica gel column chromatography and remove the hexane with a rotary evaporator. If I've understood correctly, this should yield highly potent, extremely pure honey oil. I'm not interested is isomerization.

The only problem is I don't have any experience using column chromatography for lipid extraction. Anyone who does, I'd welcome a tip or 3 sentence how-to. It would be useful for others too!

If you have no idea what I'm talking about you can look here:

Soxhlet extractor - Wikipedia, the free encyclopedia
Rotary evaporator - Wikipedia, the free encyclopedia
Column chromatography - Wikipedia, the free encyclopedia

Yeah some of the equipment is kind of expensive but I'm of the philosophy to do things right or not at all.

Thank you!

I think I found the answer, for anyone interested in producing the highest-quality possible honey oil. This page and flash movie carefully explains the steps:

Column Chromatography

So the best procedure would be to:

• Run the cannabis through a Soxhlet extractor using hexane as your solvent (easier, healthier, safer, and more efficient/selective at extracting THC than butane or other alternatives).
  
• Process the result of the extraction with a rotary evaporator, sometimes called a rotovap for short.
  
• Process the result of the evaporation with column chromatography, stacking the column, from top to bottom with: sand, silica gel, sand, cotton. Add hexane to the top of the sand before you add the honey oil as a buffer. Attach a syringe to the bottom of the column to pull the oil through.
  
• Process the result of this once again through the rotovap to remove the hexane.

What you have at the end of this process should theoretically be a somewhat reduced, but extremely pure, clean, and potent honey oil.

Silica gel is kind of expensive, but you can find it at electronics stores. A bonus is that apparently it should work pretty well for curing; if you threw a packet into a mason jar with the bud it should absorb the moisture as it comes out of the bud. Much more exact than "open the lid every once in a while". :)

Here's another helpful instruction (hey both from Canada what the heck)

Sephadex Chromatography

According to some extraction methods I found people use Sephadex for the chromatography filter although regular silica gel was more common.

Apparently, this is how the government (National Institute on Drug Abuse) makes hashish when it needs it for research purposes:
SpringerLink - Journal Article

This guy (Robert A. Nelson) wrote some pretty solid sounding instructions roughly based off of this method also:

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6.2 Extraction ~

Cannabis must be dried be it is extracted, because it is not possible to remove more than 50% of the cannabinoids from fresh material THC-Acid is difficult to extract If you plant to convert the THCA to THC, the plant material should be thoroughly decarboxylated by heating it under nitrogen at 105° C for 1 hour before performing a solvent extraction.

Chloroform is the most efficient solvent for the extraction of THC from cannabis. A single extraction will remove 98-99% of the cannabinoids within 30 minutes. A second extraction removes only 88-99% of the cannabinoids within 30 minutes. A second extraction removes 100% of the THC. Light petroleum ether (60-80°) also works well, but a single extraction removes only 88-95% of the cannabinoids; a double extraction removes up to 99%. Ethanol also can be used, but it removes ballast pigments and sugars which complicate the purification of the resin (11, 12)

Extract the dried cannabis with a suitable solvent for several hours at room temperature or by refluxing. Filter through charcoal to clarify the solution, then chill overnight to precipitate waxes, then filter the solution again. Concentrate it to one-half volume, and extract it with 2% aqueous sodium sulfate (to prevent oxidation). Separate the aqueous layer, and strip the solvent. The residue is crude hemp oil.

The odoriferous terpenes can be removed by steam or vacuum distillation. Cautious distillation in vacuo yields a fraction of crude red oil (bp 100-220° C/3 mm). This can be purified by redistillation or column chromatography. Use ethanol to remove the residue from the flask while it is still hot. Filter the solution through charcoal, and strip the solvent. Distill the residue to yield pure red oil (bp 175-195° C /2 mm). Distillation must be stopped if smoke appears, indicating decomposition. (13, 14)

Because THC is heat-sensitive, it is preferable to isolate the cannabinoids by column chromatography. The simplest method of column chromatography is performed with ethanol and ether extracts of hemp on alumina, yielding two major fractions: (1) chlorophyll, CBD, and CBN, and (2) THC. A second, more difficult method is performed on Florisil (use 10 times the weight of the oil) with the solvent system hexane:2% methanol. This yields a doubly-concentrated, viscous oil which can be repeatedly chromatographed on alumina to separate the THC and CBD. (15)

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I was going to post the link to the Robert A. Nelson page... but you already found it. :clap::thumbsup:

You might want to use a "C-18 Sep PaK", because it's nonpolar and will retain the THC, then you could run something like toluene or something even less polar through, but you'd have to then precipitate out the THC, which I really wouldn't know how to do.

Supplies to do this wouldn't be that much. A plastic syringe, polar or nonpolar column, plastic tubing,

Well hexane and chloroform are both extremely nonpolar, is there an advantage over those?

I've seen in the best quality instructions I could find TsOH being used for isomerization.

The expense I was referring to was for the rotovap and Soxhlet extractor. The column chromatrgraphy setup doesn't look *that* cheap, but the cheapest of the set. If I found it all used I think I'm lookin at $800 minimum. I think it's worth it though. I don't like working with crude home-setup approximations when you're dealing with chemistry - especially when the product is going into your body.

Do you have any experience using any of this equipment or procedures for the purpose of making honey oil?

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Well hexane and chloroform are both extremely nonpolar, is there an advantage over those?

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If I were you, I'd look up the polarizability for a bunch of differnt common liquids and use one that pretty close to what THC is or less.

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I've seen in the best quality instructions I could find TsOH being used for isomerization.

The expense I was referring to was for the rotovap and Soxhlet extractor. The column chromatrgraphy setup doesn't look *that* cheap, but the cheapest of the set. If I found it all used I think I'm lookin at $800 minimum. I think it's worth it though. I don't like working with crude home-setup approximations when you're dealing with chemistry - especially when the product is going into your body.

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Wow! Idea it would be that expensive. If you can, look around to find a cheap nonpolar column. I've used them in labs before, and they didn't seem that high tech.

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Do you have any experience using any of this equipment or procedures for the purpose of making honey oil?

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Not for honey oil, but this thread def has me thinking about ways to extract pure THC off the buds. I'm thinking that maybe you could do something like this, but you'd draw the THC out of cannabutter.

The butter base would be good because all the THCA would be thoroughly decarboxylized which is a requirement for efficient extraction.

That chemist said that chloroform extracts 98% of THC on its first pass. It sounds like that number is coming from somewhere, and it sounds like he knows what he's talking about so I'd go with that.

If you ran dried, ground bud through a Soxhlet extractor with a solvent that targeted 98% of the THC, then through a rotovap, then through column chromatography and rotovapped it again you'd have something pretty damn close to pure THC.

The next step after that would be isomerization, which involves a separatory funnel and tosic acid. It sounds kind of like a pain in the ass for the volume of product that you get. According to one guys experiments the result is a product so pure that you could dip your finger in it, lick it and be stoned. Isomerization also, apparently, creates a high that is much different from smoking THC along with the other cannabinoids. That's why I'm not interested in it.

Chemically pure THC is a transparent oil and gets even more complicated to produce than what you go through with isomerization, though that's a precursor. This guy explains it pretty well:

Amazon.com: Cannabis Alchemy: Art of Modern Hashmaking: Books: Gold

If you don't have access to a lab though it sounds like the setup would be pretty expensive.

That's why my goal is just the very pure non-isomerized honey oil. It's sounds like it'd be PLENTY strong without going through all that extra effort.

Any advice on what is meant by this:

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Concentrate it to one-half volume, and extract it with 2% aqueous sodium sulfate (to prevent oxidation). Separate the aqueous layer, and strip the solvent.

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I know sodium sulfate becomes aqueous in 7 pH water - beyond that I'm lost. Isn't concentrating and stripping the solvent the same thing? Isn't stripping the solvent HOW you concentrate it? Is the sodium sulfate so that when you use heat to evaporate the solvent (65 C for chloroform) there are nucleation sites available?

Also, is this image the proper setup for an evaporation?

I went from honors bio to AP bio in HS because I was friends with the teacher, skipping the chem pre-requisite. Why? The chem teacher told every class their first day that he guaranteed everyone would fail. 95% did. Total asshole and GPA suicide

Sorry, I was pretty high last time I posted, so my post sounded pretty stupid;)

Looking at what would have to go into this, you might not yield that much thc from the amount of bud you will be using. I think to make this worth it, you'd have to use some very potent bud, and then the yield from each level of filtration will be less than the original amount, meaning you might lose 10 or more dollars out of every 50 you invest in bud. If you are willing to spend some money to get high like very few have ever done in this country, then I say you should go for it.

Just think about this. If extracting pure THC was easy or even remotely cost efficient, then we'd see a lot less green on the streets b/c moving clear THC would be much easier to make money off of.

I agree, and I think that reasoning is sound.

I think a further reason that you don't see clear/pure THC oil, is that pure THC will yield a high that is not necessarily as enjoyable as the high you get with the intoxication of the other cannabinoids - there are other psychoactive cannabinoids.

People who take Marinol pills, which are purified THC and sesame oil, describe the experience as taking a long time to set on (maybe the result of gastric administration :)) and the high being so intense it was scary and unenjoyable. If that weren't the case, the continued press for the legalization, besides access and cost issues, wouldn't continue. My dad had cancer and was prescribed Marinol for nausea, but bought some bud and smoked it instead because he said he didn't like the effect of the pure-Marinol THC.

Also I think maybe it's a psychological thing. Kind of like at a secret santa people like to get the biggest box. When you buy bud and get a big hefty smelly bag of green I think there's some kind of gratification in that, which doesn't come with buying a little vile of clear liquid. There are other benefits also- buying something straight off of a plant it's easy to tell that it's not laced with something, you can see what you're getting. I guess with other, hard drugs, you just hope what you bought doesn't kill you. You'd be creating that situation with marijuana if they sold it in clear oil form.

That said, I think with just a hot plate, beaker, Büchner funnel flask, charcoal, chloroform, and Graham condenser (for refluxing), you could make some extremely clean, potent honey oil (especially if you started with a strain like Cinderella 99) and those things combined don't cost that much, maybe $150-200 used. The Soxhlet and rotovap would be nice but not really necessary, and too expensive to buy per the advantage if you don't already have access to that stuff. The column chromatography is chiefly for separating the THC from the other cannabinoids- so if you're looking for a more potent version of the high you normally get from smoking you wouldn't want that anyway.

Yes I realize that this is a very old thread, but I am sure there are new generations of little kids getting all excited about cannabis, googling the hell out of it, and falling asleep to dreams of the most ultra-potent honey oil known to man.


Let me first give you the, unfortunately negative, "death of your dreams" comment that all forum posters hear:

its never gonna happen, its a waste of time and money, and its too difficult if you are asking questions on a forum.


with that said, I will answer OP's question.

OP wants to do "Flash" chromatography, which is a bench-top procedure that is used all the god damn time in chemistry labs of all shapes and sizes all over the world. easily the most common method of chromatographic separation.

it requires a relatively large amount of solvent. it is also very sensitive to the amount of material you are trying to separate. 10 grams is about as much as you could ever separate using flash chromatography.

most people separate about 500 mg to 1 gram at a time (maximum). They do make columns designed for larger loading, but they are hilariously large. 10 gram column loading will require a column with about a 10" diameter (they call them "horse dicks" or "donkey dicks" because they are soo big). these are usually also at least 2 feet in the length of the main column section.

you need somewhere in the neighborhood of 0.5 to 1 mL of dry silica per miligram of material to be purified... this is a very general rule of thumb, and some labs use a different metric. it depends on what and how much you are purifying. keep in mind, "donkey dick" columns can hold about 20 liters (pi*(12 cm)^2*50 cm volume ~ 22 liters).

when you buy silica, as a researcher, you buy big fucking barrels. literally. big barrel. like 2-3 feet tall, 3 feet in diameter. big gigantic plastic barrels full of the stuff.

most O-chem labs have MANY MANY of these big barrels. so that gives you an idea of how much and how quickly you use this stuff.

basically, if you are going to purify 500 miligrams, you would use 250 to 500 mL of dry silica. if you are going to purify 10 grams, you would want to use around 10 liters of the stuff.

you would then pour hexane into the dry silica to make a "gel" or "slurry."

you put a cotton plug at the spout of the column (the "bottom" where stuff comes out), pour a little bit of sand or sodium sulfate on top... then pour the slurry on top of that.

you then "pack" the column by agitating it, causing any voids or bubbles to collapse, so that the density of the silica slurry is more or less even throughout the entire column length.

people usually achieve this by banging on the column with the palm of their hand (we used to tap on it with our cork-stands). you do this for a few minutes, making sure to get it as even as possible on all sides and parts of the column length.

you then pour sand/sodium sulfate on the top of the slurry to "protect" its surface


now, at this point, you should still have a little bit of solvent visible above the layer of the silica/sand, because you packed it in and so it condensed a little bit. You should push this layer of solvent down to just barely above the silica/sand (the top of the column packing) with the air pressure. do not push it further.

you must obviously have the stop-cock open to allow the solvent to run through, but immediately turn it off as soon as the solvent has been pushed to the correct level.

you then dissolve your mixture (BHO) in the solvent system you will begin with (say, hexane:ethylacetate 75:25 or something).

you then put the air-pressure on to push the visible solvent so that it is JUST BARELY above the surface of the sand/sodium sulfate layer (DO NOT push it all the way into the layer, this "dries" the column and ruins everything).

again, you must open it and close it during this procedure

you then add the first batch of your solvent system to the bulb (most flash columns have a "bulb" at the top, so that you can add enough solvent to keep it going for a while).


you then begin pushing it through and collecting fractions.

Periodically you will have to add more solvent.



so if you do the math, purifying 10 grams of material with flash chromatography is expensive as hell. In solvent and silica alone, I am thinking something like $500 to $1000 for 1 single extraction.

the column would probably cost around $200. and you are going to have a hell of a time evaporating the LITERAL gallons of eluted solvent without a rotovap (which cost around $5000 if you include everything, from the rotating section, to the condenser, to the collection flask, to the vacuum pump)




Chromatography is always expensive and time consuming. When they make drugs on the large scale, they usually try to avoid it, because it is so expensive to use chromatography. Even the most ridiculously huge factory-sized columns can only purify 1-100 kilgrams at time...

any chemical produced on the thousands or hundreds of thousands of kilograms per year scale DOES NOT USE chromatography at any point in its synthesis.


purifying 1 kilogram of material requires a 1-2 foot diameter, 3-4 foot long column at about 3500 PSI or more. its the type of thing that requires a mechanical engineer to design.

thank you - very much for following up on this and giving up-to-date info

other than using chromatography is there any other ways to simply remove dye and sugars from QWISO? (using ether, would a process using acid/base to move actives through different fluids work?)

If you don't know proper lab technique and safety don't attempt any of this. I knew a really smart guy who made a mistake with a solvent that was heavier than air and a burner sitting 20 feet away. He almost blew himself up.

Gordonliu makes a lot of good points. I think however the costs of column chromatography are not as high as his estimates. The solvent that comes out of the bottom of the column can be fed back into the top until one of the layers of your column makes it to the bottom. The rotovap we used in the lab also condensed the solvent after evaporating it so the losses were small.

I haven't actually tried this but I don't see why you couldn't reuse the column after you flush everything through it. I sometimes dream of owning a rotovap. What I would try doing if you're trying to make the purest honey oil you can is soak your cannabis in the solvent, filter out the cannabis, and then evaporate most of the solvent. Then take what's left and place it on top of your column and run the same solvent through. This way you know everything will dissolve into your solvent and your column will be clean when you're done.

I would suggest doing some sort of wash after you make your extract. Some solvents are very harmful, especially when inhaled, so you want to be sure your final product is clean.

I've seen butane extractions produce very high quality oil. I would try butane before chromatography, its much easier to do and since butane evaporates at room temp you don't need the rotovap.