Chromatography Forum

Another question regarding column packings. I realize that C8/C18 is the best starting column packing for development. However, if you're dealing with bases of very similiar structure and charge (+1, nearly same pKa's), and want to utilze an SCX, what would be the most powerful means of controlling selectivity (improved resolution)? Given that charges are a basis of separation on such packings, could one control selectivity proficiently, in light of the very similiar structures and single charges (MW~1000) with other varied parameters? If so, what would one use to control retention and selectivity most proficiently?

Thanks alot in advance for the feedback!

Phil

DO NOT ENTER! WRONG WAY!

Philip,

Mixed mode columns will provide you with both interactions reverse phase and ion-exchange. You can control both interactions by changing amount ACN, buffer concentration and buffer pH:. Primesep columns have both hydrophobic chain and ionizable groups (basic and acidic with different pKa)

http://www.sielc.com/Technology_2D_Properties.html

Here are examples for separation of isomers:
http://www.sielc.com/compound_216.html
http://www.sielc.com/compound_037.html
http://www.sielc.com/compound_143.html

Check other applications:
http://www.sielc.com/Applications_By_Compound.html


Contact me if you have questions

Regards,

Vlad

The three main controls for an ideal SCX column are cation type, ionic strength and pH. The first two affect the competition for the stationary phase. pH affects the charge on the analyte. In the real world there is no ideal ion exchange column, and other effects do apply.

Ion exchange chromatography is complex. Go to the library; the answers you need are too complex for the kind of casual instruction you can expect on this forum. Then go to the lab. Of course, we will be happy to help when you get stuck.

Mark, thank you. Look forward to talking in the future.

Regards,

Phil

All, thank you. Appreciate the feedback.

Regards,

Phil