Is it possible to seperate a mixture of two organic compounds (with and without amino group) using amino- functionalized silica gel column chromatography?
Which one will I get after the column?
What is the nature of the compounds? amino silica is good at scavenging electrophiles. also if you can separate the compounds in normal silica (see on TLC) it is much more economical since amino-silica is considerably more expensive than regular silica
Amine functionalized silica gel can certainly be used for this purpose. It has different "selectivity" than regular silica. If the compounds are cleaned before running on the "amine" column, the packing can be reused, in a similar fashion to C18.
You can do method development for amine columns using amine TLC plates. Amine columns can be run with organic solvent, or run with solvent systems containing water. If the compounds are polar, the amine column may run as HILIC. If the compounds are non-polar, amine functionalized silica will run as if it were reverse-phase. If run in organic solvents, amine columns run as normal phase.
Amine TLC method development:
http://www.teledyneisco.com/en-us/liquidChromatography/Chromatography%20Documents/Posters/Method%20Development%20Strategies%20for%20Amine%20Bonded%20Phase%20Columns%20for%20MPLC%20Poster.pdf#search=amine
Selectivity difference on amine compared to silica, run as HILIC:
http://www.teledyneisco.com/en-us/liquidChromatography/Chromatography%20Documents/Application%20Notes/HILIC%20Purification%20Strategies%20App%20Note.pdf#search=amine
You could, but it's not necessarily a good solution. You should get both compounds from this chromatography.
Though most amines can be purified on a standard silica-gel column poisoned with ammonia. In short, you saturate solvent like dichloromethane with ammonia (or methanol with 0.05M ammonia, but it still stinks quite badly and is way too light for easy process), then add silica gel to it and make the column. Acidic centers in silica gel will be bound by ammonia and amine will not stretch out. Another way for this is using 1% of triethylamine it all of your eluents to block all of the acidic centers in column with it.
If you have a good separation in the TLC then you may not go for it but you can go for the one that is suggested by Mikhail Nekrasov that is using silica gel column poisoned with ammonia.
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