i like this post (click again to cancel)
0
i dont like this post (click again to cancel) remove favorite mark from this question (click again to restore mark)

Hi All,

I would like to get suggestion about how to integrate the peak area of CDCl3 which is overlapped with other peaks?

Thanks.

asked Jul 19 '14 at 07:04

Jiping%20Yang's gravatar image

Jiping Yang
1


4 Answers:
i like this answer (click again to cancel)
0
i dont like this answer (click again to cancel)

Hi, If the 2 peaks are not completely overlapped, you can try deconvolution to have separate lineshape and integration. Most of NMR softwares can do if, if yours don't I recommand DMFIT (free and works quite well) http://nmr.cemhti.cnrs-orleans.fr/dmfit/default.aspx

If deconvolution doesn't work, or if the peaks are completely overlapped, you can try temperature change which may move one of the peaks...

Good luck Anne

link

answered Jul 19 '14 at 21:21

Anne%20Baudouin's gravatar image

Anne Baudouin
36

i like this answer (click again to cancel)
0
i dont like this answer (click again to cancel)

Hi Jiping, if you cannot separate these peaks using deconvolution or by changing the solvent, there is another technique which is actually superior to any deconvolution of NMR spectra. Providing that you have knowledge of the spin-system(s) involved, you can use computational spectral analysis to explicitly assign all overlapping peaks and optimize the populations of solute and solvent signals. This method can completely remove the correlation between solute and solvent peaks and thus provides the most accurate quantification in cases of severe overlap and higher order effects. Please let me know if you need further information. All the best, Matthias

link

answered Jul 28 '14 at 01:19

Matthias%20Niemitz's gravatar image

Matthias Niemitz
1

i like this answer (click again to cancel)
0
i dont like this answer (click again to cancel)

Hi there, You could use Mnova which will automatically detect the solvent signals just by running an automatic Peak Picking. Then, in the integral options, you could exclude the solvent signals. Finally, integrate the region of interest and the solvent peaks will not be taken into account for the integration.

You could also use the 'multiplet analysis' tool, which by default does not take into account solvent signals. Here you can see an example of a triplet (which integrates by 1H) which is overlapped with the solvent signal (highlighted in red):

https://db.tt/KbOyaBUb

For further information, please get in touch with Mestrelab support department:

Regards, Pablo

link

answered Jul 28 '14 at 23:35

Mestrelab's gravatar image

Mestrelab
56

updated Jul 28 '14 at 23:40

i like this answer (click again to cancel)
0
i dont like this answer (click again to cancel)

If total overlap is a problem then I would modify your solvent. A few drops of a different solvent may move your signal considerably (CHCl3 in CDCl3 7.27, CHCl3 in DMSO 8.35, CHCl3 in MeOD 7.88). Warming may also help. You would only need to move it a little to allow deconvolution using something like MNova.

link

answered Sep 10 '14 at 03:53

John%20Hollerton's gravatar image

John Hollerton
96

Your answer
Please start posting your answer anonymously - your answer will be saved within the current session and published after you log in or create a new account. Please try to give a good answer, for discussions, please use comments and please do remember to vote (login to vote)
toggle preview

Tags:

×1

Asked: Jul 19 '14 at 07:04

Seen: 9,272 times

Last updated: Sep 10 '14 at 03:53

powered by CNPROG