[ayl08]

Hi all!
I am trying to come up with a method that can tell me the amount of a few components in water. I am reaction glycerol (1,2,3-propantriol) with ammonia solution with a catalyst, in hopes to get amine-sustituted propane substituents (e.g. 3-diamino-propandiol, 1,3-diaminopropanol, 1,2,3-triaminopropanol)

What would be the best analytical method to find out the concentrations of my products?
I tried GC but the peaks were very broad and overlapping.

[Dean]

An analytic problem. HPLC-CAD, HPLC-ELSD, or optimization of GC condition(temp.,column)

[Arkcon]

If you're producing a decent quantity of mixture, maybe you can fractionally distill and collect measurable volumes?  If their boiling points are easily distinguishable.   But like Dean: said, a better idea would be better GC optimization, unless you're for some reason lock out of optimizing the GC conditions.  Distillation is just a quick way to get a ballpark for what is happening with your synthesis.

[ayl08]

Thank you very much!
I'm now trying HPLC-UV with derivations.

[Dan]

I would probably do the reaction in D₂O in an NMR tube (and determine the product ratios by NMR analysis).

[MOTOBALL]

I think that this is readily solved by GC/MS of the N,O-trimethylsilyated reaction mixture.  Blocking the N-H and O-H bonds will give you sharp chromatographic peaks.

MS will give you M+ or [M - Me]+ peaks and recognizble fragmentation patterns.

Remember the nitrogen rule: even MW requires even N atom count (0, 2, 4 etc).  Conversely, odd MW requires odd N atom count (1, 3, 5 etc).