Column Packing Techniques

[M. Farooq]

Hello,

Does anyone know of a good resource for column packing methodologies for LC (slurry packing). My interest is for ion chromatography stationary phases. Some of the people when asked said it more art and magic rather than science. Of course the composition of slurries are trade secrets but is there some "science" i.e. the physical properties requirements of packing compositions.

We use non-conventional stationary phase for exploring the properties of stationary phases which has a very high density and use water but the results are not satisfactory per se.

Any suggestions would be helpful.

Thanks

[Chris0000]

Hello

I just know the packing of preparative columns ( I.D. 2cm and more)

With a DAC ( dynamic axial compression) packing station there is no magic, its very easy:
Just put the slurry into the column an compress it with the hydralic piston.
The trick: work quick in order to prevent partial sedimentation in the slurry.

In my experience the packing stations of the diffrent suppliers are very similar, for the slurry, I would recommend IPA for sillica based materials ( RP and NP). For your special case its hard to say - you should get a smooth emulsion, maybe trying is the best way.

best regards
Christian

[HW Mueller]

Christian, are you using the word "emulsion" as a synonym for slurry, or are you implying that these paricles form emulsions like charged macromolecules?

[Boloro]

Is so surprising to me
Bcse I do column packing almost everyday. It takes a half hour at most. Results're good enough. I have never thougt it cause a problem to someone.
I think.., u just maybe your aceton (i don't know what solution u use) not so good. All my initial packings result have a problem bcse of aceton

Best regard
Bolor

[Vlad Orlovsky]

In order to pack any silica you need to do some sedimentation studies and find to solvent, in one you are looking for the biggest volume of settled particles (slurry solvent) in another oneyou are looking at the smallest volume of particles (pusher). Look at most common organic solvent. You might need to spend a week to complete this.
Find waht is emchanical stability of your silica, you don't want to crush them during packing. 400 bar should be good enough for 100-150A silicas, for 300A and up you might need lower pressure (150-250 bar)

[M. Farooq]

It would have been lot easier if the stationary phase were conventional i.e. silica or polymer based columns. The difficulty arises with other inorganic oxides supports like TiO2. They are quite dense.

What I presume that one has to find a composition in which sedimentation is slowest? Is this right?

Thanks.

In order to pack any silica you need to do some sedimentation studies and find to solvent, in one you are looking for the biggest volume of settled particles (slurry solvent) in another oneyou are looking at the smallest volume of particles (pusher). Look at most common organic solvent. You might need to spend a week to complete this.
Find waht is emchanical stability of your silica, you don't want to crush them during packing. 400 bar should be good enough for 100-150A silicas, for 300A and up you might need lower pressure (150-250 bar)

[Uwe Neue]

There is a chapter on column packing in my book on "HPLC Columns". It tells you what parameters you need to vary.

You do not need to find a composition that gives slow sedimentation. You need to find one that gives adequate sedimentation speed. If you manipulate the viscosity, the speed of packing also changes with the viscosity, so there is no gain. You just need to be in a good operational range for your equipment.

The selection of the best solvent for the slurry is rather empirical, but you can find the rules in my book.

[M. Farooq]

Thanks for the reference. I checked our library but it doesn't hold this title. I have seen your chapters in other encyclopedias. Have you written a similar chapter on column packings elsewhere?

Thanks.

There is a chapter on column packing in my book on "HPLC Columns". It tells you what parameters you need to vary.

You do not need to find a composition that gives slow sedimentation. You need to find one that gives adequate sedimentation speed. If you manipulate the viscosity, the speed of packing also changes with the viscosity, so there is no gain. You just need to be in a good operational range for your equipment.

The selection of the best solvent for the slurry is rather empirical, but you can find the rules in my book.

[Uwe Neue]

Unfortunately no.