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Author: Subject: Stationary for aqueous normal phase or reverse phase column chromatography
goldberg
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[*] posted on 28-4-2018 at 13:25
Stationary for aqueous normal phase or reverse phase column chromatography


Hello everyone
I was not sure if this is right place for this topic so if i choosen wrong forum, sorry.

I read about aqueous normal phase chromatoraphy in gereal but i'm not able to find
information about materials for column other that silica hydride.
The only alternative is TiO2 that look intresting.
It is described in paper "Chromatographic behavior of xanthines in aqueous normal phase chromatography using titania stationary phase" by Maguy Abi Jaoudé; Jérôme Randon from 2011.

I have no access to silica hydride columns so i'm thinking about peparing column with alternative material. Derivation of silica gel seems as hard topic, reagent that reacts with SiO2 are not something that i would like to mess with.
That's why i got intrested in titania based columns.
Has anybody experience with preparation of such columns?

I'm intrested in reverse phase chromatography but again C-18 surface is used most often and i'm looking for alternative.
I found mention about 'porous graphitic carbon' but without any futher information.

I would like to make dry column/flash chromatography with low pressures, not HPLC.

As far as inderstood for reverse phase chromatography i need material that is porous and non-polar, right?
How about activated charcoal? Or precipitated metals? If i correctly understand urushibara nickel for example has quite rich structure.
Would be possible to use such precipitated metal (urushibara nickel or other metal prepared in similar fasion) as stationary phase?

I'm intrested in separation of organic compound, especially ones involving amino functional groups.
And i would like to use column for mostly prepartive chromatography.

I tried to look for scientific articles about novel materials for this type of chromatography but without any success.

I'm glad to hear any recomendations for other materials and Your experience with this topic.
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beerwiz
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[*] posted on 4-5-2018 at 23:44


You can try activated alumina.
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User13579
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[*] posted on 5-5-2018 at 13:19


Yeah basic alumina would be your best bet for amines. If you look into the history of chromatography though you'll see that all sorts of column material (and eluents) have been used historically. Inorganic salts have been used, sodium carbonate I've seen used; anything not soluble in the eluent, essentially. There are books on this topic that I could point you to if you'd like, but for practical purposes you should probably just get basic (sometimes called calcined) alumina. You can also condition a column with additives such as Vaseline, for instance, to change its polarity too, again there are books on this that you can read if you're interested. Manually mixing graphite with stationary phase has been used. I've read of experiments using TiO2, it has a low resolving ability I believe, but it'll work if you use enough - but a better one that you might like to try is talcum powder, which is not too dissimilar to florisil. I wouldn't waste money on reverse phase silica column material, personally. Why do you want reversed phase anyway? Basic alumina and ethyl acetate/hexane will work well for most amines.
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Reboot
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[*] posted on 5-5-2018 at 13:23


Quote:
As far as inderstood for reverse phase chromatography i need material that is porous and non-polar, right?


Not necessarily porous, as long as the particle size is small to produce a large surface area (for more interaction opportunities between the stationary phase and the solvent.)

Quote:
How about activated charcoal?


Activated carbon will permanently adsorb most things, so that likely won't work.

I would expect most organic amines to run OK on a traditional alumina or silica column, but it could be an interesting thing to experiment with. :-)
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goldberg
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[*] posted on 30-6-2018 at 03:27


Sorry for not responding for so long time but last months were very busy for me.
Silica and alumina are polar, so how i can use them for reverse phase?
This same with talc.

I'm intrested in using water and alcohol based eluent.
Does it make sense to try to use precipiated metals prepared in similar manner to urushibara nickel?
(i'm thinking about copper)

Or to coat silica/alumina with some hydrocarbon like vaseline/parrafin?
Like mix them together, then apply heat to melt hydrocarbon and next apply some pressure.

Also it would be great if someone can recommend me good book to start witth.
There are plenty of them and i do not know what to choose for start.

Or organic amines does not separate well in reverse phase?
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[*] posted on 30-6-2018 at 04:53


Quote: Originally posted by goldberg  



I have no access to silica hydride columns


Does anyone?
Is this a language thing?
Do you mean things like octadecylsilane derivatised silica?
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goldberg
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[*] posted on 30-6-2018 at 05:10


Yes i mean derviatised silica of this type.
I read about preparing it but i do not have access to suitable reagents and they does not look like something i would like to mess with.
That's why i'm looking for alternatives.
I had searched hard literature but without success. I only have found paper about TiO2 that i mentioned.

I had a look at polymer and silicone foams but they are all unfortunately rather polar.
If there is just need for long aliphatic group how about preparing fine powder from stearic acid(or first decaroxylate it)?
I'm thinking about melting it then use compressed air to force it through small nozzle and quickly cool down tiny droplets.
I did not heard that someone had attempted such thing...

Any other ideas are highly welcome.
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alking
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[*] posted on 30-6-2018 at 13:40


If you're trying to separate amines why would you want a reverse phase system? They would come out last, that's exactly the opposite of what is desired.
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goldberg
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[*] posted on 3-7-2018 at 23:32


Thanks for reminding me of that. First of all i hoped that it would be possible to use water and alcohol based eluent that will be significantly cheaper than non polar solvent. Liter of isopropyl alcohol cost much less than liter of heptane...
Anyway thanks for help :)
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