Chromatography Forum

I would like to know how you pack the dry gravity column...do you use vacuum or just the solvent?

thank you

I would like to know how you pack the dry gravity column...do you use vacuum or just the solvent?

I think your question answers itself; if you use a solvent, it's not dry.

I would like to know how you pack the dry gravity column...do you use vacuum or just the solvent?

I think your question answers itself; if you use a solvent, it's not dry.

I mean that I do like this, the entire column is packed dry, that is,
without any solvent. Then the solvent is allowed to percolate down the column slowly, until the column is entirely moistened. My question if its a good idea to apply vacumm for help to pack the silica gel before poure the solvent

It is obvious you are packing your column at atmospheric pressure or under low pressure...to protect the soft packing material (Sephadex or similar type material comes to mind). However, using your approach, the material will swell many times within the column. Do let me know if you are successful this way.

Depends on the packing. Some materials (gel-filtration media and ion-exchange resins, for example) can't be dry-packed, as sfe-co2 pointed out.

Other materials, (silica, for example) can be successfully dry-packed. Application of vacuum to the column outlet along with a vibrator was the standard technique for packing GC columns when I started doing chromatography (circa 1970). For dry-packing LC columns, we didn't use a vacuum (the column diameter was to large for it to be effective). The standard approach was "rotate, bounce, and tap" to get a homogeneous bed.

Yes Tom, column packing techniques have come a long way haven't they? Nayra, I suggest looking through literature sources for what you wish to do. Professor Georges Guichon's (USA) and Dr. Andrew Shalliker's (Aust) groups (and others of course) have done very interesting studies in this regard. Also, try and grab hold of a book by Uwe Neue (HPLC Columns - Theory, Technology, and Practice, Wiley-VCH, 1997)....a good source if you wish to head down this path. Good luck.

If you pack silicagel in a glass column, use a slurry in methylene chloride for packing, then change the solvent without letting air inside the phase. Don't use vacuum.