not sure how to use amino(NH2) column

[moon704520]

here I am going to use an amino(NH2) column250*4.6,can it be used as RP /NP separation?is there any special considerations about how to clean ?how to store the column?is there any difference how to use this kind of column ?
any suggestions will be highly appreciated!thanks

[Bryan Evans]

NH2 columns are used for normal phase applications. You should check with your manufacturer to see what solvent the column was shipped in.

Silica based NH2 columns traditionally have not been stable and are prone to bleeding (ligand desorption) when exposed to water. As a result, one will see a loss in retention over a short period of time. Polymerically based NH2 columns are more stable, but suffer from poor efficiency.

Unison UK-Amino is silica-based (high efficiency), but also durable in highly aqueous eluent.

Storing your NH2 column in a non-aqueous storage solvent will help with the column lifetime.

[Bryan Evans]

For uses of NH2 phases:

1. aqueous normal phase (e.g. saccharides)
2. normal phase for less polar samples
3. weak anion exchange

[Noser222]

If you search this forum you'll find a few posts about troubles with amino columns, from myself included.
One thing that can save you some trouble is, if you want to analyze carbohydrates or otherwise run in aqueous or HILIC mode, to buy an amino column that is for that purpose. Switching them from normal phase solvents can be a pain, in my experience.
I personally like the Shodex Asahipak. It is polymer based, so you can clean it at pH 10-12. For monosaccharides, I've gotten much sharper peaks than with the conventional silica-based aminopropyl.

[Bryan Evans]

The chromatogram below compares a 5um NH2 column vs.
Unison UK-Amino (3um silica):

http://www.silvertonesciences.com/files/TI313E.pdf