Would someone please share their experience with these types of columns? I’m aware of the supposed upside, but I would like to know anything regarding to their shortcomings. I’m currently working on a method using a Supelco RP-Amide C16.

they are wonderful columns for things like small aliphatic acids that require 100% water to get adequate retention. AquaSep by ES Industries is the most retentive of the columns we evaluated and my personal favorite. It, and others, seem to have excellent life for doing acids in 100% water with phosphoric acid.

Prism, by Keystone, seems to have residual basic sites. In water/phosphoric acid we have separated inorganic ions with these columns to demonstrate the presence of these sites. Because of the potential mixed mode for retention and hence unpredictable performance we tended to not use Prism columns. I am sure they must be good for some things.

I have no experience with Supelco column.

The properties of many of these columns are summarized in J. Chromatogr. 868(2000)41-50.

Aquasep appears to be somewhat different from the majority of polar embedded phases & uses an embedded ether functionality rather than the more basic (N) funtionality of most others. I understand that the ether was conceived to address the issue of 100 % aqueous mobile phases rather than to provide alternative selectivity. Other manufacturers have addressed the issue of 100% aqueous through the use of 'polar endcapping' (e.g. Aqua, Aquasil etc). These types of columns are useful for the separation of very polar species under RP conditions.

The RP-Amide-C16, Prism, SymmetryShield etc are members of what I would call the 'true' polar embedded class in that the embedded functionality is amide or carbamate based.

The polar embedded phases can be used in the same fashion as any other RP phase. However, one word of caution - the bonded phase is more susceptible to hydrolysis (at lower pHs). I suggest trying to maintain a pH no lower than pH 2.5 if possible. Certainly if these are to be used at pH 2.0 - 2.5 then do not use elevated temperatures.

I hope that this helps.

I've used several of these water-friendly columns, and they are not all alike. The AquaSep from ES Industries has been a favorite of mine as well, and it has lasted for quite a while.

Keystone's Aquasil column worked well, but it did not last very long. The Keystone Prism column DOES have residual basic sites; it does not work well with acidic compounds.

I just recently received a free Polaris column from MetaChem/Ansys, and it gives some great separations, but it's durability is still being tested.

I've worked with the RP-Amide C16 column and I have had good luck with a variety of separations, but these columns are not as rugged as something like an Inertsil column. First, they need to be stored in NEAT acetonitrile every time - no water, no methanol. When I use this column, I usually program an acetonitrile wash into my method to ensure that there are no problems. Still, I will typically get several hundred injections on this column. I've tried others and they do neat things as well, but for a few applications, this is a favorite of mine.

Good Luck!