Why use Petroleum Ether for Chromatography?

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Howdy Friends

I’m about to take the plunge into straight phase chromatography over silica 60. For separation of cbd from thc.

I’ve read/heard from a few sources that a 95-98% petroleum ether with 2-5% diethyl ether can get resolution on a 48"+ length column.

My question is why use Petroleum Ether (a blend of pentane, hexane, and trace heptane + others) over something like straight hexane/heptane.

Is there something specific with the Dielectric Constants of the blend? Is there any reason to use that over other traditional alkanes I’ve got on hand?

Thanks!

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Actually no

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Awesome thanks!

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Care to elaborate? Or… You just going to do what you do?

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I’m satisfied with this one :slight_smile:

Chill errbody!

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my famous tlc plate used hexane for excellent separation. a 48" column is quite oversized too

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I’ve heard d8 and d9 is separable at that length. Hoping to get myself a 99% d9 on this one :slight_smile:

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yessir

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I would expect nothing less…
I’ll leave it at that… I don’t feel like dealing with intelligent ignorance today

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you can separate those on a shorter column. tlc gives clean baseline separation on 6cm already

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Sweet. Well now I can dump some fat loads into this bitch.

In a manner of speaking.

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make sure you don’t overload, capacity scales with diameter, not length

i.e. girls love fat dicks more than long ones

sort of

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I’ve got a 6" (WIDE!)

Hoping a kg will fit. I’ve heard it should be adequate.

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absolutely not

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Need to go bigger diameter?

The resolution ends up being a bit of a function of both width and length no?

If I run a lower DEE gradient over it, it should move slower, but with higher resolution, over a longer distance?

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Probably smarter just going wider I guess.

1 large pizza is more surface area than 2 mediums with πr^2 and all that.

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assuming a volume of 1000ml, the height of the band alone without silica is already 5.6cm.

assuming a sg 60 density of 0.5 and a pore volume of 0.75ml/g, you’ll need 1.3kg = 2.6 liters of silica to absorb that liter, so basically more than 15% of your usable column height - not taking into account solvent volume.

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33 posts were split to a new topic: Roiplek and cattrap argue

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I’m going to uh, ignore most of the above, and point out that you’re free to use whatever you want. Quite a few papers report excellent separation and purity (98-99%).

The way i figure it, it removes the guesswork as a starting point. If you decide to join the dark side: 99:1, 98:2, 90:10.

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You start low and work your way up on the DEE yah?

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