June 15, 2009
by Arvin Moser, Team Manager, Application Scientists, ACD/Labs
One of the trickiest parts of interpreting NMR data is identifying what signal belongs to the unknown compound and what can be classified as an impurity. In this case, impurities are described as extra signals coming from a solvent(s), a side product(s), extraction/purification process, etc.
The 1H NMR spectrum below is for an unknown compound. The spectrum shows a highly coupled system with the exception of two singlets at 2.14 and 1.68 ppm. In addition, the integrals of the 2 singlets show a relative integral of 1 proton. This indicates the possibility of 2 CH groups adjacent to 3 quaternary carbons. Although is not necessarily incorrect, it does raise 2 yellow flags that either singlet (or both) does not belong to the unknown. The next step would be to check this possibility against 2D NMR data.
Dear Sir,
Thank you for sending me valuble information .I request u to send previous information also.
One more thing sir, can u please explain me what is meant by FIELD GRADIENT(FG shimming) in nmr and its role in 2D masurements?
I will be waiting for u r answer .
Your’s Sincearly’
CH.RAGHU
Hello Ch.Raghu,
Thank you for your interest in the P2C2E blog. If you sent me a previous question, I did not receive it. Can you resend it to me?
As your question is specific to the NMR instrument, I offer three websites, listed below, that may answer your question.
http://www.nmrwiki.org/wiki/index.php?title=Main_Page
http://u-of-o-nmr-facility.blogspot.com/
http://www.cis.rit.edu/htbooks/nmr/chap-7/chap-7.htm
Regards,
Arvin