Urgent :Equivalent column for Acclaim Mixed-Mode WAX-1

[anjie]

Can anyone reccommend an agilent column that is equivalent to Dionex Acclaim Mixed-Mode WAX-1 , 2.1 by 150 mm column.
Need an urgent reply
Thanks a lot

[nschwartz]

I doubt if they would have an equivalent. Looks like a very unusual type of column.

[XL]

Hi Anjie,

There is no equivalent column for Acclaim Mixed-Mode WAX-1 in the market. Is there any reason that you need an equivalent column? I will try to answer any questions regarding this column and any other Acclaim columns. Feel free to send me an email if I can be of any help. My email is xiaodong.liu@thermofisher.com. Now Dionex is a part of Thermo Fisher Scientific.

[Vlad Orlovsky]

Lets be fare to competitors

As far as I know at this point Agilent does not have such columns, but there are several equivalents to this column and I don't know why XL say that there is no such thing. SIELC produces 3 different equivalents to Acclaim WAX-1 and Imtakt produces one column. Dionex even comparing their mixed-mode columns in almost every publication to SIELC equivalents.

We are talking about mixed-mode column which is a reversed-phase anion-exchange column with carbon chain and basic group on the surface. In case of SIELC and Dionex both functionalities are assembled on one ligand. The difference is in position of basic group, it is either closer to the surface (SIELC) or away from the surface (Dionex). In case of "close to the surface" approach, basic group shields all silanols from interacting with your analyte. Retention time for compounds is controlled by amount of ACN, amount of buffer, nature of the buffer and buffer pH. Here is schematic for benefits of mixed-mode:
http://www.sielc.com/Technology_2D_Properties.html

SIELC introduced these column back in 2003 when nobody had new generation of WAX or WCS mixed-mode columns. I belive that Dionex introduced equivalent of Primesep WAX columns in 2007.

Please look at applications for Primesep D, Primesep B2 and Primesep SB column, may be you will have something you are looking for:
http://www.sielc.com/Applications_By_Column.html

Contact me if you have questions.

[XL]

It is apparent that Vlad has different opinion on the meaning of "equivalant." I won't say C18 column is equivalent to a polar-embebedded RP column becuase they often exhibit different selectivity. The same rule applies here.

If the question were "what is the equivalrnt column for Primesep B" I would provide the simialr information on Acclaim Mixd-Mode columns as the way Vlad did, except that I wouldn't claim they are equivalent but present it as an alternative.

[Vlad Orlovsky]

The request was for something else than Dionex Acclaim (Agilent in particular). Agilent does not have a WAX column as far as I know, so I suggested the equivalent. I can take both columns and by playing with amount of acetonitrle, buffer pH and buffer concentration achieve VERY similar or even the same selectivity of separation. Alternatively I can guide people to do the same.

Anyways. there are 1000s of C18 columns on the market and everybody claims "equivalency". They have diffrent loading, end-capping, pore size, pore volume, surface area, etc, but manufactureres still claiming equivalency for the purpose of method development.

According to the dictionary:
http://www.merriam-webster.com/dictionary/equivalent

Lets state the facts and you can correct me if I am wrong:

1. Both columns are based on silica gel with similar carbon load, surface area and pore size
2. Acclaim and Primesep WAX columns have carbon chain, which provide reversed-phase interaction
3. Both columns have basic group on the surface which provides anion-exchange interaction, pKa of this basic group is the same for the practical purposes of ion-exchange mechanism. pKa is about 10 and your mobile phase is usually at least 4 units away from pKa of the column.
4. Basic groups provide shielding effect of silica surface, and that is why it has less influences by source of silica

People are usually asking for equivalent columns for one of the following reason ( I don't know what was Anjie's reason):

1. Need to validate method on two different columns in order to have a back up in case something happened (very often a requirement in pharma companies)
2. Columns are not available for particular customer (delay in shipment, no stock in particular country, or problem with manufacturing)
3. Columns are expensive and less expensive alternative is required/available
4. End user had bad experience with particular company in terms of quality of the product or quality of the support (reproducibility, longevity, etc.)
5. Other reasons

So from my experience Acclaim WAX-1 and Primesep columns (reversed-phase/anion-exchange one) are equivalent to each other, and even Dionex salespeople stated about equivalency. When somebody asked for equivalent of Primesep columns. So if somebody states that Acclaim is equivalent of Primesep, so opposite should be true.

here is funny equivalency statement:
more cheese=more holes, more holes=less cheese concluding more cheese=less cheese

Lets give customers a chance to decide.

Enjoy your weekend!

[Kelly Johnson]

I am not sure if your specific column is included but the USP has a helpful database to compare columns:

http://www.usp.org/USPNF/columnsDB.html

Good luck!
Kelly