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Using Peak Deconvolution to Extract the 1H Count

August 18, 2009

When you work on enough NMR datasets, eventually you will run into cases where peaks are overlapping. One approach is to apply a peak deconvolution (or fitting) algorithm in an attempt to separate out the contribution of each overlapping peak.

The 1H NMR spectrum below shows a multiplet (dd) nearly buried by a large water peak at 3.30 ppm.

DeconvolutionAnd1HCount_1_Aug182009

Direct integration of the multiplet will give a skewed value due to the contribution from the water peak. If the multiplet at 2.87 ppm equates to 1 proton, then how many protons does the multiplet at 3.24 ppm equate to?

The calculation is shown below:

1. Total RA = Relative Area(Water) + Relative Area(dd)

= 134.85 + 13.98 + 13.54 = 162.37

2. Total DA = Deconvoluted Area(Water) + Deconvoluted Area(dd)

= 30077 + 403 = 30480

3. (Deconvoluted Area(dd) / Total DA) = (Relative Area(dd) / Total RA)

Relative Area(dd) = 403 * 162.37 / 30480 = 2.14 ~ 2 protons

DeconvolutionAnd1HCount_2_Aug182009

 

4 Replies to “Using Peak Deconvolution to Extract the 1H Count”

  1. Hello Arvin,
    I have just discovered your science blog last few days ago.
    and thanks alot, for giving me so much idea on the structural elucidation part, as i’m totally a newbie.
    I would like to ask on the article entitled “Using Peak Deconvolution to Extract the 1H Count” on 18th of Aug, 2009.
    May i know what is the deconvoluted area of the solvent peak and my target peak??
    How could i calculate it out???
    Thank you very much and i’m looking forward to your reply.
    Regards,
    Hoey

  2. Hello Hoey,
    Thank you for taking an interest in my blog.
    To answer your question, deconvolution is a process to extract individual peak information in cases where peaks are overlapping. It is described in detail in the link below. Many NMR software packages offer the deconvolution tool. ACD/Labs offers the NMR processing software for free to academics at: http://www.acdlabs.com/resources/freeware/nmr_proc/index.php .
    http://acdlabs.typepad.com/elucidation/2009/08/using-peak-deconvolution-to-extract-the-1h-count.html
    Regards,
    Arvin Moser

  3. Hello Arvin,
    It is a very useful blog. Could you please elaborate on how you got the peak area? Basically how was the deconvolution performed? It would be very helpful if you could respond back.
    Thank you and awaiting your reply.
    Swati

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