one question about sec

[HW Mueller]

Andy, what do you mean with "actively adsorps" and
"so there's no way to avoid it with carbohydrate-based SEC media."?
You don´t think it is possible, as I noted in my last statement above, that there should be a solvent which shifts the equilibrium completely away from the stationary phase to the mobile phase?

[Andy Alpert]

Please see my response in the related discussion string today.

[bhuvfe]

do you mean you recommend use offline MS to check GPC fraction after Ve.

If money is not a problem:
- GPC-MALLS will shed some light on the separation mechanism.
- If your polymer is very low molecular weight (< 5000 Da) LC-MS
might help.
- MALDI after GPC fractionation could help too

For some reason I assumed you were interested in synthetic polymers
and what I advised was going in that direction. Reading one of your other posts it seems you want to use GPC as first separation/clean-up and then focusing mainly on small molecules (natural products?).
MS should help you for small molecules. Ionic strength, pH, organic modifier should help to control the separation mechanism.
Unfortunately, I think it will be a trial-error approach.. As already stated above the information from the supplier of the column and from some literature search (or book) will be your best starting point.

Any chance to use organic GPC? I find that it’s less prone to non-SEC effects (at least for my products).

[HW Mueller]

Strange, I don´t understand how my statement of 2:35 am got into both chains???