First attempt at chromatography

Not sure if this one is any good, is this what it looks like when you do it?
Started as a dark red 68%.
I used alumina, water and acetone. Waiting for tlc supplies to arrive still.

How gradual do gradient s need to be to separate THC from CBD?


I think you should get a longer thinner column. While this may be good as a filter aide, I don’t think you’ll get good enough separation on a packed glass buchner. You want enough head space to not disturb your bed and allow for a more even pack. You may even want to invest in some sand to pour over your resin to act as a defense against accidental aggressive solvent pours if you’re not using a pump.


might be a better bet for a column


I read someone advise 2-3 inches is sufficient, but not sure what they were getting out exactly. I definitely did not load my sample properly, I mixed it with celite but I didn’t use enough and get an even layer. Looks like I got some color out, but I think I lost alot of product. I loaded 25 g. I need to either chrome out the THC or clean up enough to get CBD to crystallize. I’m hopeful, I think this might could work with some practice

To piggy back onto this, if you are building your own column I would also suggest using a thin layer of styrofoam (smaller than the diameter of the column) that can sit at the top of the stationary phase, or will float with any mobile phase, and you can use it as essentially a barrier as you add your product so it doesn’t disturb the head of the packed column.


Cool tip, had not heard that one yet

Looks like you still have some gunk left on the column. You should flush while it’s still wet, prob with pure acetone. I’m not familiar with alumina but a good practice with liquid chromatography columns is to keep them wet at all times, so store it plugged. The packing tends to form cracks otherwise

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2-3” in width or length? from the way i understand chromatography the name of the game is to have enough residence time to claim everything. not enough time in the column won’t pull everything

2-3 inch tall for a dcvc method is what I heard

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Yeah, I went up 80% before I ran out of acetone. How do you calculate optimal solvent volumes for each gradient?
I was mixing by volume, is that how it’s done? Or do you weigh it?

And that is a gunked up piece of filter paper on top, I placed right under the sample/celite mix

If you do this, be very mindful of the solvent system that you’re using. Acetone (which OP is using) and many other common solvents will simply dissolve the styrofoam!


Yes of course, that was just a quick example. I used to use that with aqueous heavy protein purification. It could be an aluminum frit or anything really. Something to sit on top of the filter media.

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@CCCBD I found this SOP to be pretty helpful.

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Good info, thanks. I don’t have any of that fancy shiz, but it’s the same fundamental s, I suppose.:+1:

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I’ve never tried with acetone, and i don’t know if it’ll work with the same water gradient.

I’d go 3-5" with the alumina in DCVC style. It works well with ethanol gradient.

Your column height should be ok though. I’ve done it on those size before.

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yeah no styrofoam here lol. but definitely the correct idea - used washed sandbox sand instead :slight_smile:

@CCCBD - yeah you aint separating shit in that. your column in this case needs to be taller and thinner. This length is directly proportional to your separation ability. also, is that celite?? or alumina? either way, no. spring for some nice c18 silica gel for your stationary phase.

before you try again, read these

and go on youtube and watch a video or two.

*im partial to dry packing btw - but either works. feel free to poke for more :slight_smile:

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I am also going to be trying a column similar to this soon. Also, I was looking into potentially using calcium carbonate as a stationary phase…

Will keep everyone updated.

3-5" of alumina will work just fine :slight_smile: no need to go a giant column if you’re using a good solvent gradient.


Wikipedia? Come on man. That was the first thing i did. It looks like they don’t even mention dcvc

  1. youre welcome.
  2. my bad i should edit my comment to re-read than, based on what you have presented. not trying to be a dick but youre miles away. start with the fundamentals.
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