I am having the same problem. When I contact GE, they told me to repack the column and yes it was expensive. So, I try to run the column up flow using water. The column was in the same position but run it from bottom to top. Its works like a charm for me. U may try all other solution above. Each of them was a very good advice. 

You probably exceeded the maximum acceptable pressure in your chromatographic runs. Try to just readjust the top column piece to touch the resign and see if your expected resolution is maintained. If the gel beads are intact, you should be able to recover your previous profiles. You can also add new resign to the top of the column. Look for the GE or Amersham troubleshooting guides. In an extreme scenario, if there is no recovery, you can also buy new resign and fully repack your column. Try to maintain good cleaning in place SOPs and clean injection samples to avoid clogging and damaging your system.

I support the hints of Paulo. You can also repack the columns if necessary. Perform a Column packing evaluation run of the column after adding column material or repacked column. There you get information about the quality of your packed column. Furthermore always and on a regular basis perform cleaning in place. (0.5 M acetic acid works quiet well). If the Column is clogged - perform a reversed flow - you can simply turn the column around and the top is the bottom and so ...if there are bubbles or particles you can remove them this way without letting the particles run through the whole column. 

What samples are you running? Do you know how the column could have got blocked? For example lipids or protein aggregates. Once you know this you can figure out a suitable (vigorous) cleaning method. NaOH, isopropanol, pepsin etc..

When cleaning run in backwards as it will probably be blocked at the top see if this works. I do not know how easy these higher pressure GF columns are to pack or if you can even repack them. From looking at the website, I personally, would advise against topping up the column with further matrix as firstly, the matrix available to buy has a 34um bead size whilst the column is packed with a 13um bead size so you will have a different resolution. Also having two settled beds could change the profile.

If you want to use the columns for practice. It may be easier to buy the 34um bead size prep grade matrix and try and repack the column fully with that. You will lose resolution and may not be able to run at high flow rates but if it is practice column that may not matter you. Also if it gets blocked you can easily unpack, clean and repack.

If any sample is stuck on the column, I would transfer  the Sephadex into a  side flask add smallish volume of  sample buffer , mix &, evacuate the slurry (rubber bung on flask )  and  repack the column, avoiding any great pressure heAD. .   Recover your sample by elution with a suitable low ionic strenght buffer under gravity flow and  monitor OD's  to  identify sample in the eluent..  RECOVER THE SAMLPLE  eg BY DIALYSIS AND FREEZE DRYING..- other wise ionexchange.   Sephadex columNS  are very pressure sensitive and  one must not exceed the recommended  pressure head. or subject the colums to undue pressure from a pump.  L. BOHM   

Thank you for all the answers.

One column, we got from another lab, and the other one has "worn" out.

Meaning, that it has not been possible to pinpoint the BC/MS/PhD student who "broke" it. Maybe it was over time. But in general, I am surprised that the column can be so damaged.

The pressure alarm om the Äkta should hopefully do the job of saving the column.

Maybe there have been some small accidents when running ethanol on, at to high flow.

Would you expect, that the medium can be rescued after a repacking?

So take it out, slurry it, clean it, and put it back in?

Or would it be definitely destroyed ?

So, there is no need to save a sample.

It is more a cost effort, of trying saving 2X 2000 euro. :-)

I am having the same problem. When I contact GE, they told me to repack the column and yes it was expensive. So, I try to run the column up flow using water. The column was in the same position but run it from bottom to top. Its works like a charm for me. U may try all other solution above. Each of them was a very good advice. 

Before taking it out from the column to repackage and risking additional damage to the beads, have you tried to just adjust the top piece of the column and assess its chromatographic resolution? Run a mixture of standards or a sample with a specific known profile and see if you really need to go for extreme measures. If so, be gentle in the cleaning steps to avoid further resign degradation.

In addition to reverse flow, one way to relieve the compression would be to shrink/re-swell the beads by increasing/descreasing salt and solvent concentration...

Hi, I'm a bit late to the discussion, but would be interessted if and how you saved the column.

Regards,

Antoine

Note that in relation to the pressure alarm on AKTA systems, they will return to a default value after the end of each run - which is usually 5 MPa. At least that's the case with our AKTA FPLC. So if people are dong a manual clean it can easily happen that system will go over pressure limit of resin. You can change the default value on the Unicorn software or at the machine itself.