Waters Atlantis columns vs Phenomenex Synergi Polar

[adam]

I was wondering if anyone had experience with the Waters Atlantis column. They claim that it has extra retention for polar analytes due to the lower density of bonding and to some kind of proprietary encapping.

It's curious to me that they use a C18 chain. If one really wants to maximize polar retention wouldn't a shorter chain also be logical. Phenomenex has a product called 'Synergi Polar' which contains a phenyl group on an ether linkage, with hydrophilic endcapping. It would seem to me this would give the most polar retention.

Anyone ever compared the two?

Any thoughts?

Thanks

[Uwe Neue]

Adam,

I do not understand your reasoning. Why would a phenyl packing with a polar group give more retention than a C18 packing? In addition, the Atlantis dC18 results in MORE retention than the highly coated Symmetry C18 due to a higher access to the C18 ligand on a loose packing compared to a very dense packing. This has been published in U. D. Neue, J. E. O’Gara, A. Méndez, “Selectivity in Reversed-Phase Separations: Influence of the Stationary Phaseâ€