Geometry and Scaling Down a TMAE column

[Chach]

We are currently Using 2 Pharmacia BPG 300 column with TMAE and Qsepharose the in our purification process and would like to run smaller columns for Process development purposes.

I know that maintaining similar geometry is important. Should I utilize a ratio between the Diameters and Bed heights of the Process Colum and the smaller columns? Also we are using and Akta Prime system for the small scale, if anyone can recommend suitable columns to use that we be great, the ones we currently have do not seem to be ideal.

Thanks

[Uwe Neue]

For scaling a separation to a column of different dimensions or for exploring a separation on a smaller scale, you want to use the exact same packing material in the smaller column. To scale to identical elution conditions, you want to keep the ratio of your gradient volume to the column volume constant. The gradient volumes are the flow rate multiplied by the gradient times.

There are a few additional usually smaller effects that come from difference in the volumes between the gradient mixer and the column top. They can be taken care of with the same thought.

[Chach]

I am fairly new to Chrom- Someone was trying to explain column volume to me, are you refering to the phyical volume when inside the column when it is packed?

[tom jupille]

The volume of liquid contained in the packed column. Approximately equal to the sum of the inter-particle volume and the pore volume.

[Uwe Neue]

For the calculations of scaling, all you need is the empty column volume: pi * R^2 * L. The underlying assumption is that columns packed with the same stuff have about the same interparticle volume. This should be good enough for your purposes.

[Chach]

For the calculations of scaling, all you need is the empty column volume: pi * R^2 * L. The underlying assumption is that columns packed with the same stuff have about the same interparticle volume. This should be good enough for your purposes.

Thanks, Pretty Straight forward,

I have been discusng this with others at work with more experience-

In Scaling down What do you think about keeping the Bed height Constant, while seting up a proportion between the radius of the Column and Flow Rate?

[Uwe Neue]

This is the simplest approach. You can keep all event times constant. All you need to do is to change the flow rate with the column cross section (or square of the diameter).