University of Ottawa NMR Facility Web Site

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Tuesday, August 28, 2007

NMR Chromatography

The DOSY (Diffusion Ordered Spectroscopy) experiment can be used to resolve the components of a mixture. The technique uses pulsed magnetic field gradients to resolve mixtures based on the different diffusion constants of the components of the mixture. The figure shows the resolution of a mixture of small molecules. The proton spectrum of the mixture is in the horizontal domain and the diffusion constants are in the vertical dimension.



5 comments:

Anonymous said...

Where does the special DOSY processing software (such as the DOSY plugin, Mnova, etc) offer much advantage over the bruker built-in software?

Thanks.

Glenn Facey said...

Anonymous,

Thank you for your question. I have never used the plugin for the Mnova software, so I cannot comment on it. I would suggest getting in touch with the good people at Mnova.

Glenn

Anonymous said...

Dear Glenn,

Thank you for sharing such an informative application of NMR.


How can we calclate the molecular weight from the DOSY NMR?





Glenn Facey said...

Anonymous,
To the best of my knowledge, there is no way to calculate the molecular weight from DOSY NMR data.
Glenn

Anonymous said...

I believe you can. However, you will need to build a calibration curve with different compounds of known molecular weight. Here is a paper that shows you how to do it: Org. Lett. 2015, 17, 1429−1432.

Hope this helps.