NuMega Resonance Labs

Proton NMR

For H-1 NMR, there are four keys aspects you have to keep in mind while interpretting a spectrum:

  • Signals: The number of unique proton environments.

  • Integration: The area underneath the curve that corresponds to the ratio of hydrogens.

  • Chemical Shift: The best estimation of functionality based on shielding/ deshielding effects.

  • Splitting Pattern: The number of hydrogen neighbors which follows the N+1 rule unless a more complicated system is present.

NMR Testing Services, Mass Spec, Elemental Analysis and Optical Rotation

Above are the relative chemical shifts for particular functional groups in an H-1 NMR spectrum. The more electronegative atoms near a proton, the more downfield or deshielded your signal will be. Unusual functionalities such as ring strain can alter expected chemical shifts. Tetramethylsilane (TMS) is a common reference standard with chemical shift at 0 ppm. Common chemicals shifts for NMR solvents include chloroform (7.26 ppm), methanol (3.34 ppm), acetone (2.17 ppm) and dimethylsulfoxide (2.5 ppm). Other common solvent shifts and impurities can be found here.