gypsyNo2
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Spinning band/centrifugal chromatography
Hey guys,
Found a spinning band chromatography kit at work today and I wanna start using it. After talking to one of the techs here they recommend that I get a
good recipe for making the plates, wondering if anyone has a recipe that's trialled and tested ?
Cheers,
GypsyNo2
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Dr.Bob
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Look at the sites below for lots of info on making radial plates and the materials to do so.
I used to use them a lot, they work OK for some compounds. Best for semi-polar, UV active, compounds. The 2mm plates are a nice compromise in
loading and separation.
www.harrisonresearch.com
and
www.ichromatography.com
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gypsyNo2
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thanks Dr.Bob, exactly what I was looking for. What type of sample loading do you get with a 2mm plate and is there a rule of thumb with the plate
size vs. sample loading ?
Cheers
gypsyNo2
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radagast
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In a previous thread on radial chromatography, Nicodem stated:
About solvent consumption for 2mm plates (it's an estimate since I never measured it):
- about 10-20ml solvent for moistening the starting line,
- sample loading (in 2-5ml CH2Cl2)
- elution generally takes something like 150-300ml (if you use gradient elution then at least double that volume)
- washing generally takes 50-150ml (depending on what you use)
With the 4mm plate its takes approximately 2 to 3 times more solvents.
See http://www.sciencemadness.org/talk/viewthread.php?tid=10030
Does your radial chromatography device use a pump, or one of those addition funnels? I recently acquired an old Cyclograph and jerry-rigged it up to
a FMI pump, but have yet to purify anything on it.
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smaerd
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A small peristaltic pump or two could really come in handy for solvent application and/or gradients.
This is a bit off-topic but I think the idea is of interest, especially concerning the cost of cyclographs.
I had an idea for creating a DIY device from a leaf-blower motor. The difficulties I could not over-come were, what could be used to make the
disc's(to apply the silica/gypsum stationary phase). Maybe a compact disc or something? Also the casing for the cylindrical device itself would not be
easy unless there was wide-gauge PVC or something similar readily available.
I did find an article where a group used a centrifuge with the top assembly removed and applied the solvent with a well-placed buret on a
ring-stand.(attached)
Attachment: A New Technique for Centrifugal Chromatography.pdf (568kB)
This file has been downloaded 711 times
A new technique for centrifugal chromatography
G. M. Christensen and R. Swor
Journal of Chemical Education 1962 39 (7), 347
Here's a another similar article:
Attachment: Horizontal Chromatography Accelerating Apparatus. Descripttion of apparatus and applications.pdf (561kB)
This file has been downloaded 740 times
Horizontal Chromatography Accelerating Apparatus. Separation of Dyes and Indicators.
J. F. Herndon, J. C. Touchstone, G. R. White, and C. N. Davis
Analytical Chemistry 1963 35 (2), 238-240
[Edited on 21-11-2012 by smaerd]
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Dr.Bob
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I vaguely remember 100 mg per mm, but I think that was overloaded a good bit. For really good separations, I would guess less than that, but that
would allow 100-200 mg on a 2 mm plate. The solvent amounts sound about right.
As for the plates, you really have to use glass, and if it is etched or roughed up by sanding, it works better. Any other material would likely
dissolve or soften under the solvents. You have to use silica with gypsum (Plaster of Paris) in it, otherwise the plates just fell apart. Even
then, when I tried to make my one, that happened often enough.
And the leaf blower motor sounds a bit over-sized, the motor in those is tiny, I would prefer a 12V DC one, where you could modify the speed a bit.
But of course, a spark-free or sealed motor is what they likely use in the commercial one.
The Chromatotrons were neat, but I will take an ISCO system over them any day, and a Prep HPLC even better. If I had a huge budget, I would go
Supercritical Fluid Chrom. as that has lots of great features like a mostly non-flammable "solvent", CO2, which goes away without much effort, usually
leaving your compound in the modifier, often methanol. And the loading is very good, higher than HPLC, better for low water soluble compounds, and it
seems to have great resolution. I have seen many grams of material separated on SFC in a short time, and the peaks all end up in MeOH, so there was
almost no effort to product recovery.
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gypsyNo2
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Cheers guys,
This has helped a lot !
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