Mixed mode columns

[KalB]

I was curious to see if anyone has recommendations on mixed mode HPLC columns.

I've been looking at the SIELC and Imtakt company information on their mixed-mode columns (e.g. reversed phase + cation exchange) and can think of a few applications where they might work pretty well.

I worked with the SIELC products (specifically the PrimeSep columns) about 7 years ago and there were some issues with column reproducibility (i.e. batch-to-batch reproducibility). Production methods may have changed since 2003.

Any thoughts or experiences will be appreciated.

[Vlad Orlovsky]

We revived mixed-mode chromatography in 2003 and since then some other companies introduced new mixed-mode column. At the beginning people were not aware about things to avoid, and used only knowledge of RP chromatography, which sometimes can cause problems with reproducibility. A typical example, use methanol on cation-exchange mixed-mode columns and uncontrollably esterifying column and changing the ratio between hydrophobic and cation-exchange properties. Another example, control of pH of the mobile phase and consideration of ionization states of the column and compounds. Also in 2004 we were forced to change silica gel support, but since 2005 are using same bare silica for all our products. There are over 60 publication in magazines about our mixed-mode columns and numerous validated method in pharma companies.
I think that mixed-mode is a valid approach which is here to stay, you just need to decide which columns/companies to try and learn how to use mixed-mode.

Here is a Newsletter : "Do's and Don't of Method Development in Mixed-Mode Chromatography:
http://www.sielc.com/pdf/SIELC_August_2009.pdf

Just visit our website and see. We added a lot of products since 2003

[XL]

Just wanted to point out that besides SIELC and Imtakt, Dionex offer an array of mixed-mode HPLC colulmns, both silica based and polymer based.

Dionex introduced a family of polymer based mixed-mode columns in 1990s. Since 2005, Dionex has been working on developing silica based reversed-phase/ion-exchange columns to address difficult applications that conventeional reversed-phase columns (e.g. C18) fail to do.

Some information on these Mixed-Mode columns can be found in the following links. There are also quite a number of publications on the applications using this columns (not listed here):

1. RP/anion-exchnage/cation-exchange trimode (Acclaim Trinity P1)
http://www.dionex.com/en-us/webdocs/707 ... 239-02.pdf

2. RP/WAX (Acclaim Mixed-Mode WAX-1)
http://www.dionex.com/en-us/webdocs/488 ... 021407.pdf
http://www.dionex.com/en-us/webdocs/813 ... PN2312.pdf
http://www.dionex.com/en-us/webdocs/833 ... PN2371.pdf

3. RP/WCX (Acclaim Mixed-Mode WCX-1)
http://www.dionex.com/en-us/webdocs/658 ... PN2024.pdf

4. RP/HILIC (Acclaim Mixed-Mode HILIC-1)
http://www.dionex.com/en-us/webdocs/618 ... PN1963.pdf
http://www.dionex.com/en-us/webdocs/614 ... _HILIC.pdf

5. OminPac columns
http://www.dionex.com/en-us/products/co ... 71739.html

Thanks for reading.

[Thom Bizly]

An additional alternative is the brand new Szidah Bedar column.

Based on a unique core material with innovative properties, this column has flow-through properties comparable to monoliths but still being a particulate material. Through a novel surface functionalisation procedure, the columns become extremely stable, tolerating a mobile phase pH from 1-14. The beneficial flow-properties speed up your separation, and it is completely platform independent. The upper pressure limit is 1000 bar, and the columns are available in any dimension.

When used in combination with the new unique mobile phase Additive Q, the complete polarity range can be explored with only one column, even phlogiston can be detected at sub-ppt levels, see chromatogram below.


More information can be found at:
www.sequant.com/SB

Best Regards,
Dr Thom Bizly

[Uwe Neue]

Nice design. I suppose we must step up our research.

[bhuvfe]

An additional alternative is the brand new Szidah Bedar column.

Based on a unique core material with innovative properties, this column has flow-through properties comparable to monoliths but still being a particulate material. Through a novel surface functionalisation procedure, the columns become extremely stable, tolerating a mobile phase pH from 1-14. The beneficial flow-properties speed up your separation, and it is completely platform independent. The upper pressure limit is 1000 bar, and the columns are available in any dimension.

When used in combination with the new unique mobile phase Additive Q, the complete polarity range can be explored with only one column, even phlogiston can be detected at sub-ppt levels, see chromatogram below.


More information can be found at:
www.sequant.com/SB

Best Regards,
Dr Thom Bizly

Great April 1st joke...

[zahra1634]

Hi ,
Thank you all .That was very useful information for me here. I was wondering if you know any mixed -mode (RP/ anion exchange) column for protein conjugate analysis.

I really appreciate it in advance.

Zahra