Chromatography Forum

Dear All,

I want to know the Equivalent HPLC Column to Primesep100 150x4.6x5micron.

Regards

P. V. S. Prasad
Hyderabad

I believe the Primesep columns are a proprietary technology (i.e., there is no exact equivalent).

Depends on what you need the equivalent column for. In many cases, you may be able to get "equivalent" results by using a standard reversed-phase column with an ion-pair reagent.

Both Uwe and Tom are right. Primesep 100 is a mixed-mode (cation exchange + reverse phase) column, so to my best knowledge there is nothing "equal" in the market.

Nevertheless, depending on the stuff you intend to analyse, you might find interesting options - either "average" reversed phase columns or others with "funny" selectivities like polar endcapping.

Actually I am supriced that nobody knows the Duet columns from Hypersil (Thermo). They supposed to have C18/SCX and C18/SAX. I am sure that there are differences between those columns and the ones from Primesep but that should be the closest equivelant column. I might even dare to say that the Duet columns were available before the Primesep columns but I might be wrong (i.e. I have seen articles back in 1997-1998 using those columns).

Vlad (SIELC-Tech) can maybe pitch in and explain the differences between the two columns (I think I know the diferences but Vlad would give a more in depth explanation).

Here is a copy paste of the column description (C18/SCX):

Hypersil Duet columns are an ideal choice for unknown compounds and metabolism studies, as they can separate hydrophobic and ionic compounds in a single analysis run. Retention of ionizable species is manipulated by adjustment of the mobile phase pH, and retention of hydrophobic compounds is control by a solvent gradient.
Duet SCX/C18 is a mixed-mode phase with 50% hydrophobic stationary phase (C18) and 50% strong ion cation exchanger (sulfonic acid). This stationary phase makes expensive and time-consuming procedures such as column switching, using ion pair reagents or using columns in series redundant.

The main application areas of Hypersil Duet lie in metabolism studies, where the main component has strong hydrophobic character but the metabolites contain ionic groups.

o Separate hydrophobic and ionic compounds in a single run
o Select from two mixed mode phases, using either cation or anion exchange combined with C18
o Retention of compounds is optimized using mobile phase pH, ionic strength and percent organic

I believe that in Primesep, the ionizable group is embedded within a hydrophobic chain. However, the Hypersil Duet phase is a physical mixture of a C18 packing and a cation exchange packing. I would guess also that it is most unlikely that the cation exchange group in Hypersil Duet is the same as that in Primesep 100. So I would agree with Tom that there is no exact equivalent of Primesep 100. This does not mean that it is impossible to achieve the separation you want with a different type of column, but it will involve you in method development. Your question suggests you would like to directly substitute a different column, which is unlikely to be possible.

PVS Prasad,
Why do you want to stop using the Primesep 100?
WK

Maybe it's not available in his country... or is too expensive overthere!

Of course, there is no true copy of a column made by another manufacturer. The same is actually true for most C18s as well. However, my suggestion came from a different angle. Occasionally, a user may want to create an "equivalent" method on a different column. You can see this as an insurance, in case the supplier discontinues the product, goes out of business, or the plant burns down.

This was the context of my proposal.

There is no exact equivalent for Primesep columns as far as we know. It is not a physical mixture of ion-exchange and reverse phase phases as everybody stated. Primesep100 has an alkyl chain containing an acidic fragment with pKa of 1. The column mimics reverse phase RP chromatography with ion-pairing reagent in the mobile phase, but does not require an ion-pairing reagent and can be used with a typical RP mobile phases.

Duet column is just a mechanical combination of two phases in a single tube. For any isocratic application Duet column is not different from any serially connected IE and RP columns. Maybe it is just little more convenient. Primesep columns are different from Duet in several aspects.

On the manufacturing end:
Columns contain only one type of packing material so they are easy to pack to obtain high efficiency and peak symmetry.
Both functional groups, ion-exchange and RP, are part of a single molecule bonded to silica gel, so it is easy to maintain exact ratio of IE vs. RP.
Strong IE functional group completely masks silanol interaction which makes Primesep columns independent of silica source as long as it is the same surface area and pore size.

On the user end:
Strong IE functional groups within RP layer attract water and make the column resistant to dewetting. The column can be used in 100% aqueous or pure organic.
Polar groups make a single column applicable for normal phase chromatography, SFC, and HILIC and RP mode.
http://sielc.com/Technology_Versatility.html

The column has IE properties and can be used as traditional IE columns (see many examples on our web site). http://sielc.com/Technology_Alternative ... raphy.html for example.
It is all in addition to main advantage of this column which is unlimited and well controlled retention of polar compounds.
http://sielc.com/Technology_RetentionOf ... ounds.html

You can benefit from multiple interactions on Primesep column:
http://www.sielc.com/Technology_2D_Properties.html

Of course, any Primesep column can be used as general RP column for any traditional RP application.

I don’t think there is a real alternative for this column, but if you are just doing a RP separation of neutral molecule, you can do it on any RP column (Waters, Phenomenex, Supelco); if you’re doing IE, you can find many IE materials (Dionex); normal phase can be done on silica gel or any other NP column; you can find many AQ type columns; but if you need a single column which can be used for multiple types of interactions, you may have a hard time finding an exact Primesep equivalent.

We have bunch of Method Development tools which might help in column and mobile phase selection:
http://www.sielc.com/Request_Literature.html


Sorry for the lengthy message

Regards,

Vlad

P.S. Our columns are available in India. I am not sure that P. V. S. Prasad has any of our columns.

Reading Vlad´s contribution it just came to me that the Pinkerton restricted access column has glycine attached to silica on the outside (of the particle) and glycine-phenylalanine-phenylalanine on the inside pores. Thus this column is sort of a weak ion exchanger/rp analog of Primesep 100. It has interesting and weird characteristics, but typical of mixed mode: Not optimal performance in any one type of interaction.

My guess is that Pinkerton column will not show anything close to Primesep in terms of retention, it is much weaker and has much less hydrophobicity so you will have hard time to have it in ionized form at pH below 5. Weak basic compounds with pKa 6 and below will either come at void or very close to it.

Hans,
I don't want to go into argument of "optimum" performance again. I am just surprised that you are emphasizing this without even trying Primesep. What are your criteria for optimum performance (peak shape, number of plates, capacity factor, surface coverage, particle distribution, etc.)? If you have any particular application, which will prove to you optimum performance of Primesep we are ready to take your challenge.

Regards,

Vlad

The thought was that the principal has existed for a long time. The Pinkerton people (Regis) can also point out advantages of their columns.
On the "optimum" discussion my feeling was that there was a consent, so no need for further discussion (Vlad, it seem that you said that you did not claim that your columns are better than the best C-18 for nonpolar substances, as an example).

This still stands: Send me a column for testing, other manufacturers have don this.

Dionex also has the OmniPac series of polymeric, mixed-mode RP/IEX columns. Another way to simulate the mixed mode is column coupling.

Another motivation for finding an equivalent may come from the Purchasing Department. They love to pressure vendors by threatening to buy from the competition.