Nuclear magnetic resonance spectroscopy overlapping signals

Mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy are well-established techniques for the identification of chemical compounds. Both methods deliver unique fingerprints of molecules and, under the right conditions, they can also be used to quantify the concentration of a compound in a mixture, if not too many substances are present with spectra that show overlapping signals. Mostly the methods are used for pure substances, although and over recent decades, the techniques have particularly been used to study biomolecules such as peptides and proteins. For mixtures of, say, more than five compounds, an analytical separation method such as electrophoresis or chromatography is required to be able to identify or quantify the compounds. 

Nuclear magnetic resonance (NMR) spectroscopy is nowadays one of the most powerful techniques available to the chemist to elucidate the stracture of organic compotmds. However, in order to measure chemical shifts, coupling constants and peak integrations, the NMR signals should be clearly separated. Overlap is not a serious problem in NMR spectra, but is more... 

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