organic salt analytical method

[guoyang]

Hi, everyone! Recently i met a compound, i don't know how to get the purity method. Could you give me some help. the structure:

[DSP007]

LC-Ms RP-18 CH3CN/H20/ ammonium acetate gradient 10%=> 90%

[Vlad Orlovsky]

Hi, everyone! Recently i met a compound, i don't know how to get the purity method. Could you give me some help. the structure:

Morpholine is not going to be retained on C18 column without ion-pairing reagent. IP reagent will make LC/MS not a favorable detection technique.
You can retain both compounds by mixed-mode approach. Morpholine will retain by cation-exchange mechanism and your acid will retain by RP mechanism. If you use TFA you can monitor these by ELSD/CAD. You will need to set up your ELSD at 35-40*C. If you have access to LC/MS you can replace TFA with ammonium formate and have retention and separation. Something similar to these:
http://www.sielc.com/Compound-Morpholine.html
http://www.sielc.com/Application-Neutra ... olumn.html
http://www.sielc.com/Application-Comple ... ounds.html

contact me if you have questions.

[juddc]

A few thoughts:

1. I'd be a little surprised to see the acid picked up by an ELS under acidic conditions with a perfluorinated IP agent. I'd worry that it would be a bit too volatile relative to the MP. Still, worth a try...

2. If you choose to use an IP agent with reversed phase, you can modulate your retention well by varying the chain length on your IP agent.

3. If higher sensitivity is needed for the acid, you could derivatize it. I'd only want to do this in a relatively simple sample matrix, however, because this would probably be a nightmare in a biological fluid. Anyway, EDC/NHS and anything with a primary amine and a chromophore would form an amide, then you could move forward with ion-paired reversed phase with UV and ELS detection. You'd need to do some validation, obviously, and also account for N-dimethylaminopropyl-N'-ethyl urea in your chromatography, which is an end product of the EDC reaction in your method. (It's detected on the ELS...)

If I was in your shoes, I'd give Vlad's suggestions a shot first, then possibly move on to what I have above.

Cheers!