How to test Water Soluble Cannabinoids on HPLC

Hi Everyone,

Quick question for you guys. Has anyone prepped a water soluble sample for HPLC analysis?

I imagine that I would want to extract into water (it’s in a powder form right now) but I’m undecided if I should include any methanol/ACN in my matrix.

Currently running a gradient of ACN/H2O with H3PO4 on a Raptor arc-18 C-18 RP from Reztek.

Tips would be appreciated, not looking for a consultation though. Thanks in advance for any advice.

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Something to keep in mind is that technically, “water soluble” cannabinoids are really just water compatible. The cannabinoids don’t actually dissolve in water. If the powder you’re testing is an encapsulated emulsion (quite likely, but not always the case), I’d imagine that mixing it with water first then doing a solid phase extraction might be the kind of direction you’d want to go towards.

You definitely wouldn’t want to just dissolve into water and test that though. It might be fine if you include the methanol and/or acetonitrile, but I’m not certain because I’m just not super experienced with HPLC. My instinct tells me it wouldn’t though, and I would imagine it would be favorable to get rid of the actual water solubles in the powder before running your sample anyway.

I’ve done a fair amount of analysis of “water soluble” cannabinoid beverages with other methods and a simple SPE of cannabinoid water products (or powder dissolved into water) always worked well for my purposes. My guess would be that the SPE route would work fine for HPLC.

If someone put a gun to my head and demanded I test your powder, I would prep an SPE cartridge with water and acn. Elute the water/powder mixture and wash the filter with more water. Elute the cannabinoids with acn and collect that. Evaporate off the acn and reconstitute with whatever is being used as the mobile phase then that is what I would analyze.

Good luck! Hope you can figure it out.

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Isn’t the sample correctly dissolving in your standard extraction solution ?