Recently I performed 1H NMR spectroscopy of a compound, having 23 Hs. The spectral data is showing tnat it has 23 Hs. Is it due to minor instrumental error or something's wrong with the compound itself?
I'm not sure I see the problem, or is there a typo in your text, and the spectra shows more or fewer protons than the 23 it should have?
There are a number of things that can cause discrepancies in the number of protons.
Exchangeable protons (OH, NH, SH etc) protons are not always seen in the spectra.
Even deuterated solvents contain some protons (typically they are only 99.8 aton-% deuterium).
Water can often be seen in the spectrum.
Your typical 1H experiment is not 100% quantitative, so especially signals containing many protons can have some discrepancies.
Small errors in calibration can add up. If you have a signal with an integral of 1, and 10% of some small impurity underneath (or if it happens to be something that relaxes slowly so that the integral is not fully accurate) an use that or calibration, then a signal with 10 protons would have an error of about one whole proton. Because of this I prefer to use the largest signal with a known number of protons for calibration.
In some cases even protons bound to carbon atoms can be exchanged by deuterium from the solvent, for example via tautomerism (acetylacetone being a typical example of this).
@Jani Rahkila Thankyou for explaining. I just checked, there was an error in the analysis. Integration was not done right. I optimized it, and now it's showing accurate number of protons.
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