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Topic: NMR versus GC/MS, HPLC/GC, HCLtitration, meltingpoint test  (Read 5441 times)

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Offline chantal

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Is it true that only a NMR test is able to detect the effectiveness, quality, quantity of a product?
That it  is able to detect  wrong raw material, over-reaction, or isomers occurring during synthesis?
But what about the other tests like GC/MS, HPLC/GC, HCLtitration, meltingpoint test. Is one or a combination of these tests not able to do the same as a NMR, tell you the effectiveness, purity, quality of a product? How do these other tests compare
to NMR?

Offline discodermolide

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Re: NMR versus GC/MS, HPLC/GC, HCLtitration, meltingpoint test
« Reply #1 on: May 19, 2012, 04:53:39 PM »
Is it true that only a NMR test is able to detect the effectiveness, quality, quantity of a product?
That it  is able to detect  wrong raw material, over-reaction, or isomers occurring during synthesis?
But what about the other tests like GC/MS, HPLC/GC, HCLtitration, meltingpoint test. Is one or a combination of these tests not able to do the same as a NMR, tell you the effectiveness, purity, quality of a product? How do these other tests compare
to NMR?


NMR provides structural information, the other tests purity information. NMR also says something about the purity, but the other systems are more sensitive and appropriate, provided you have a pure sample of the material under investigation.
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Offline fledarmus

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Re: NMR versus GC/MS, HPLC/GC, HCLtitration, meltingpoint test
« Reply #2 on: May 21, 2012, 07:50:20 AM »
Is it true that only a NMR test is able to detect the effectiveness, quality, quantity of a product?
That it  is able to detect  wrong raw material, over-reaction, or isomers occurring during synthesis?
But what about the other tests like GC/MS, HPLC/GC, HCLtitration, meltingpoint test. Is one or a combination of these tests not able to do the same as a NMR, tell you the effectiveness, purity, quality of a product? How do these other tests compare
to NMR?


NMR provides structural information, the other tests purity information. NMR also says something about the purity, but the other systems are more sensitive and appropriate, provided you have a pure sample of the material under investigation.
And pure samples of the impurities you are trying to detect. The other tests you mention may tell you that you have impurities present, but unless you have samples of the expected impurities to compare them to, they give you no information on the identities of the impurities. If you are worried about which of two isomers you obtained and do not have pure samples of both isomers to compare, the NMR will give you the structural information you need to make that determination. Same with wrong raw material, or unexpected products resulting from over-reaction.

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