Sciencemadness Discussion Board

remove ion pairing reagent after pre-HPLC my products

RabbitTy - 22-9-2019 at 23:20

I have some inpurities need to be separated by pre-hplc.
Sodium 1-heptanesulfonate and Potassium dihydrogen sulfate been added to enhance the separation.
However,I need to remove ion pairing reagents.
My products are alkaline
Mobile phase is 71% Acetonitrile and 29% water.
could anyone help please.

DavidJR - 23-9-2019 at 11:05

Best approach would be to come up with a HPLC method that doesn’t require any nonvolatile additives.

unionised - 23-9-2019 at 12:15

Quote: Originally posted by DavidJR  
Best approach would be to come up with a HPLC method that doesn’t require any nonvolatile additives.

That's about as much help as saying "if you don't mix them, you won't need to separate them".

You can often remove ion pairing reagents using an ion exchange resin.
Depending on exactly what they are you might be able to do something like the classic "alkaloid" extraction.

If you are really really lucky, just adding an alkali like NaOH to deprotonate the material then adding excess sodium chloride and cooling the mixture will get it to separate into two layers (CH3CH doesn't mix with salt water)
and you product will dissolve into the ACN, leaving the other stuff in teh aqueous phase.

[Edited on 23-9-19 by unionised]

DavidJR - 23-9-2019 at 14:36

Oh I know, but it’s true, isn’t it?

RabbitTy - 23-9-2019 at 16:52

Quote: Originally posted by unionised  
Quote: Originally posted by DavidJR  
Best approach would be to come up with a HPLC method that doesn’t require any nonvolatile additives.

That's about as much help as saying "if you don't mix them, you won't need to separate them".

You can often remove ion pairing reagents using an ion exchange resin.
Depending on exactly what they are you might be able to do something like the classic "alkaloid" extraction.

If you are really really lucky, just adding an alkali like NaOH to deprotonate the material then adding excess sodium chloride and cooling the mixture will get it to separate into two layers (CH3CH doesn't mix with salt water)
and you product will dissolve into the ACN, leaving the other stuff in teh aqueous phase.

[Edited on 23-9-19 by unionised]


Thx！My products are cyclovirobuxine D and analogues. Alkaloid~Could u please introduce me some method of Ion-exchange resin.

RabbitTy - 23-9-2019 at 17:31

Quote: Originally posted by DavidJR  
Best approach would be to come up with a HPLC method that doesn’t require any nonvolatile additives.


Ive tried several different mobile phase type.Only with ion pairs could my product be separated.Its alkaloid with some analogues. The main component is cyclovirobuxine D.

DavidJR - 24-9-2019 at 06:44

There are volatile ion paring reagents though, mainly perfluorinated straight chain carboxylic acids...