soma
Hazard to Others
Posts: 297
Registered: 31-7-2010
Member Is Offline
Mood: No Mood
|
|
best way to pack a chromatograpy column
I've seen several methods: slurry; dry pack - adding adsorbent 1st , then eluant - or adding eluant 1st, then adsorbent.
Any preferences?
|
|
|
phlogiston
International Hazard
Posts: 1379
Registered: 26-4-2008
Location: Neon Thorium Erbium Lanthanum Neodymium Sulphur
Member Is Offline
Mood: pyrophoric
|
|
What kind of column? Are we talking HPLC columns with micron-sized particles? nano-LC? Or mm - cm diameter columns with large particle sizes?
I assume the latter, because I think you would have been more specific otherwise.
I prefer packing it as a slurry in the mobile phase you want to use, because some column materials expand or contract when they are wetted or
equilibrated. This can result in bubbles or cracks in your stationary phase and cause excessive peak broadening.
If the column needs to be kept cold during the separation, make sure to cool everything down well before packing the column, eg. overnight in the cold
room. Then make sure it never warms up, not even briefly. Otherwise, you may have bubbles form in the column due to gasses that were dissolved in the
equilibration buffer.
[Edited on 18-11-2016 by phlogiston]
[Edited on 18-11-2016 by phlogiston]
-----
"If a rocket goes up, who cares where it comes down, that's not my concern said Wernher von Braun" - Tom Lehrer |
|
|
laserlisa
Hazard to Self
Posts: 52
Registered: 5-2-2016
Member Is Offline
Mood: No Mood
|
|
Wet packing (slurry) all the way!
|
|
|
Metacelsus
International Hazard
Posts: 2539
Registered: 26-12-2012
Location: Boston, MA
Member Is Offline
Mood: Double, double, toil and trouble
|
|
Yep, slurry is definitely best.
|
|
|
Fulmen
International Hazard
Posts: 1716
Registered: 24-9-2005
Member Is Offline
Mood: Bored
|
|
I have only added slurry to the mobile phase. The other methods might work, but I've never experienced problems with the wet method.
We're not banging rocks together here. We know how to put a man back together.
|
|
|
Maroboduus
Hazard to Others
Posts: 257
Registered: 14-9-2016
Location: 26 Ancho Street
Member Is Offline
Mood: vacant
|
|
Heat generation can also be a problem pouring solvent into some dry packed columns.
This can also contribute to the problems mentioned above.
|
|
|
soma
Hazard to Others
Posts: 297
Registered: 31-7-2010
Member Is Offline
Mood: No Mood
|
|
Thanks for the responses.
Another question.
Would there be a problem in preparing the column and leaving it for many hours before using it? (Keeping a layer of solvent above the silica).
|
|
|
alking
Hazard to Others
Posts: 252
Registered: 11-3-2016
Member Is Offline
Mood: No Mood
|
|
I pack columns with a slurry, packing dry is always a bad idea imo. I do pack smaller burettes dry however.
|
|
|
Scalebar
Hazard to Self
Posts: 54
Registered: 6-5-2016
Location: Europe!
Member Is Offline
Mood: Looking for a way out
|
|
For our size exclusion columns it's wet pack from slurry using a reservoir on the top, if you want to show off you can start messing with ramping the
pressure to control the shape of the peak as it elutes ( but it is way too much effort ). We keep packed columns for years - as long as they never run
dry.
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
