Chromatography Forum

diol-modified silica based SEC or sephdex column?

Sephadex is not hydrophobic - it is a dextran polymer bead (glucose polymer). There are some treated sephadexes - lipophilic sephadex as an example. That said, I don't think it can take the pressure of an HPLC - it is more of a low pressure to medium pressure support (100 psi max).

Actually it is the other way around – it does not exhibit too strong flow resistance, hence the pressure doesn’t get too high.
You can apply several mL/min flow (all depending on the column dimensions of course) without even getting close to the pressure limit.
So, it is the flow rate that is important and not the pressure.

Best Regards

Actually it is the other way around – it does not exhibit too strong flow resistance, hence the pressure doesn’t get too high.
You can apply several mL/min flow (all depending on the column dimensions of course) without even getting close to the pressure limit.
So, it is the flow rate that is important and not the pressure.

Best Regards

I do agree with you up to a point. Depends on particle size - I am a protein chemist so I have worked with sephedex for a long time (at least 15 yrs.). It is pressure limited because of compressibility (like polystryrene columns) and therefore can have issues.

It is pressure limited and so are all other materials. Sephadex is more susceptible to high pressures than silica based materials for instance. But my point was as follows:
High pressure per se is not a particularly desirable goal. If you can apply the desired flow rate in order to achieve a certain separation, efficiency or whatever, then the pressure is of no concern, as long as it is within the material’s limits. Reworded, the pressure is a consequence and not a goal.

Best Regards