Chromatography Forum

Hi,

I am curious if there is an advantage in using a polymer (aphera from supelco) column instead of a silica based column (i.e. hypersil bds) for separating a pegylated molecule MW ~ 10K da.

The method utilizes C8 with ion pairing reagent ocante sulfate sodium salt.

I can't see how interaction between the polymer column and polymer molecule would have improved selectivity over a Si column.

Since silica columns have more substitution, more C8 groups, shouldn't it be more selective (i.e. higher plate count, more ion pairing) to use that with the ion pairing reagent?

Thanks,

What are you using for detection? One advantage of aphera and polymeric columns in general is that they have much better performance than silica columns by light scattering detectors, ie, better detection limits.

I am using UV detection.

Isn't the advantage you are talking about related only to the detector? Or are you trying to say that a polymeric column will have less peak broadening? That would certainly provide better resolution with related substances.

Could you clarify how the detector improves the columns performance?

Yeah... I'm only talking about the detector. The claims that I have heard are that silica sheds off particles which result in poorer baselines with ELS detection. Whether this is true or not I do observe 10 to 100x lower baseline noise with polymeric vs silica materials with ELSD. No help to you hear I'm afraid.

Oh I see. Well that is good to know, anyway. Thank you.

think about the totally different chemistry