Chemical Forums
Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: ayl08 on April 08, 2013, 10:36:06 AM
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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.
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An analytic problem. HPLC-CAD, HPLC-ELSD, or optimization of GC condition(temp.,column)
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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.
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Thank you very much!
I'm now trying HPLC-UV with derivations.
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I would probably do the reaction in D2O in an NMR tube (and determine the product ratios by NMR analysis).
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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).