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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
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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

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answered Jul 19 '14 at 21:21

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Anne Baudouin
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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

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answered Jul 28 '14 at 01:19

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Matthias Niemitz
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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

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answered Jul 28 '14 at 23:35

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Mestrelab
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updated Jul 28 '14 at 23:40

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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.

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answered Sep 10 '14 at 03:53

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John Hollerton
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Asked: Jul 19 '14 at 07:04

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