How can one determine quantity of an organic molecule by its NMR spectra?

[9106]

quantity , as in how much? with the its NMR spectra information

[Blank B]

You need to have a calibration curve or at least a comparison.The area of a peak (the integration) in NMR is quantitative, that is, the more sample you have, the bigger the are would be. just like how the area of signal of 1 proton is smaller than the signal of 2 proton.So you just have to compare the the integration of a specific peak of your sample to the standard or to the standard calibration curve"The most important fundamental relation of qNMR is that the signal response (integrated signal area) Ix in a spectrum is directly proportional to the number nuclei Nx generating the corresponding resonance line:Ix = KsNxwith Ks as a spectrometer constant"Journal of Pharmaceutical and Biomedical Analysis 38 (2005) 813–823

[Tony N]

Proton (H) NMR and Carbon NMR can roughly tell you the number of hydrogens and carbons in the compound but if the compound has symmetry all the hydrogens and carbons will not show up. The only way to find the actual quantity such as mass of the compound is through mass spec

[laurbrown]

I think you can only determine the quantity by using an internal standard in your NMR sample. You need to put a known quantity of a standard in, and then you can compare the integral values of your known standard to your unknown molecule.(integral value of standard proton) / (integral value of unknown proton) = (# of moles of standard) / (# of moles of the unknown)Using this equation and plugging in the integral values of one standard proton, one unknown proton, and the number of moles of standard will tell you the number of moles of unknown in the solution.
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