Yields on chroma?

for those out there conducting flash chromatography for separation of minors (i know very rare), what are your yields looking like?

Just looking for other values to compare to, I’d like to see how shitty or great my yields are in comparison (which are at about 24% considering starting material is at 20% concentration)


I’m confused. You’re getting a 24% return? Are you losing 76% of your useful input?

If so… Stop doing what you’re doing

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sorry, so I run a gram at a time on 84g of c18. of that gram of material ran, only 200mg of it is of interest.

24% return on that 200 mg, hope that clears it up.

hahaha well looks like I’ll need to do some more hw in that case thanks for the honesty tho :rofl: :+1:t4:

you should be able to get in excess of 80% efficiency, so you should be able to get 160mg of that 200mg out, what solvent system are you using? Is it isocratic or gradient? How many column volumes are you doing per run? I can probably recommend some improvements, especially if your efficiency is that low

If I may ask, why are you using reverse phase silica for isolating cannabinoids? even the acids are separable on standard phase silica 60 in my experience. Reduce your solvent polarity by a smidge and add a few drops of acetic acid (only if you’re separating acids)

Agreed, your efficiency should be MINIMUM 80%. We shoot for 95%.

Might be worth checking if your 24% potency result is accurate, or maybe you are isolating a different compound than the compound testing at 24%.


H20 (50mM ammonium formate) and MeOH.

DI-H20 has been modified to hit a pH of 6.2, roughly the same pH as my LC grade water (figured that would help out the cause). I did run w/ lc grade water but wanted to see if I could reduce solvent costs by using just DI water. MeOH is ACS grade.

10 CV in total for a single run (1 CV = 120 mL)

2g of starting material embedded onto DE (solid loading is suuuuper helpful) on top of 82g of c18.

  1. 32/68 for 4.4 CVs

  2. 15/85 for 4.4 CVs

  3. 5/95 for 2.2 CVs

and prior to going thru 1 thru 3, I run what i refer to as a “prep” gradient to kinda get the c18 ready and conditioned for the run. that would be 3 CVs of the initial step (so 32/68 in this case)

just using nitrogen to move the shit, pressure regulator tops at 20 psi.

I was never successful running normal phase, but I hear you.

if NP was possible media costs just went down substantially.

but I probably fucked something up, im already at 24% yields shit.

I was running EtAoc/hexanes. (quite frankly, i’m not sure if I attempted a dry loading method w/ sil60. I’ll have to look back at my notes, but I was not happy trying NP it was never successful for me). no additives were ran w/ the mobile phase as well.

Could you share which minor you’re trying to isolate? Maybe I could help.