separation of diammoniumcations

[schnippy]

I try to find a suitable method for the separtation of diammoniumcations. These products were formed in an benzylation of diamines. I'm interested in a separation an analytical (HPLC) and also in a preparative scale. Has anybody an idea?

[Uwe Neue]

A reasonable standard application for a similar problem is the analysis of paraquat and diquat. Several methods are around, including MS-compatible methods. The simplest one uses an ion-pair reagent. Since you want to do prep, you probably want to work with a high ion-pair reagent concentration to obtain a good loadability. The disadvantage of this method is that you get your amine with the ion-pair reagent as the counterion.

An alternative method for the paraquat-diquat separation uses silica as an ion-exchanger, i.e. with a reversed-phase solvent.

Both methods have been developed at Waters, and you should be able to find at least the first method in the Chemistry eApplications Notebook.

[SIELC_Tech]

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