Coulmn Backpressure problem

[chetan_m43]

Dear All,
I am working with production scale DEAE ion exchange chromatography. The problem we are facing is that, when the column is packed, we are not able to get the optimal operating flow rate. We have check for any problem with pump and skid but they are operating at their design specification. However when fluid is pass through the column either in upflow or downflow we are not getting the flowrate. We pack this column at 3 bar.

My question is, in what way resin might be contibuting to backpressure? is reducing packing pressure will help? If piston is withdrwan to what extent it will effect the column efficiency?

Will really appreaciate some guidance on it.

[tom jupille]

in what way resin might be contibuting to backpressure?

Some possibilities:
- it might be overpacked.
- it might have a lot of fines (broad particle size distribution)
- it might have been packed at a higher ionic strength and now be swelling.

[chetan_m43]

Thank you tom jupille; for your valuable suggestion. Can you also let me know how I can prove and convince my management that resin might have fines particle in it. As I have already suggested this possibility but they are rulling it out saying its a new resin and has been used only for 18 chromatography cycles.

Packing at High Ionic strength: During packing we have used 20% IPA to make slurry, will that have any effect.

Regards,
Chetan

[tom jupille]

Can you also let me know how I can prove and convince my management that resin might have fines particle in it.

As a "quick and dirty", suspend some of the resin in buffer, pull an aliquot, look at it under a microscope. The let it settle for a while, pull another aliquot of the supernatant, and look again. That won't be quantitative, but it will give you an idea.

During packing we have used 20% IPA to make slurry, will that have any effect.

Yes it can, but what that effect is depends on the crosslinking, the ion exchange capacity of the resin, and what the ionic strength of the buffer (the other 80%). That kind of question is best addressed to the manufacturer of the resin since they will be the most familiar with its properties and limitations.