NMR lab tool
Compare observed ¹H and ¹³C NMR chemical shifts with peer-reviewed residual-solvent and impurity data. Results are possible matches, not definitive assignments.
Matches are tentative and require confirmation. A peak may correspond to a listed impurity or to a compound outside the reference dataset.
Inputs
Observed peaks
Interpretation note
This finder reports possible matches, not definitive assignments. When you have both spectra available, check whether the same candidate also makes sense in both 1H and 13C NMR before assigning a residual impurity.
Results
Possible assignments
How to read this
Enter a solvent and one or more peaks to see ranked possible matches.
Method
How matches are ranked
The finder compares each entered chemical shift with the reference peaks for the selected nucleus and deuterated solvent. Candidates with more matching peaks and smaller deviations rank higher. The tolerance is a search window, not a confidence interval.
Interpretation
Chemical shifts vary with concentration, temperature, water content, pH, and sample composition. Confirm candidates from multiplicity, relative integration, additional peaks, and, when available, agreement between 1H and 13C spectra.
Dataset version 2.1, released 21 July 2026. Numerical data are compiled from three peer-reviewed sources:
- Gottlieb, Kotlyar and Nudelman, J. Org. Chem. 1997, 62, 7512-7515
- Fulmer et al., Organometallics 2010, 29, 2176-2179
- Babij et al., Org. Process Res. Dev. 2016, 20, 661-667
Source tables were transcribed into local spreadsheets, normalised for solvent, nucleus and compound labels, and loaded without interpolation. Each result retains its source field.
The local compilation is provided for interactive searching. Reuse and redistribution conditions are under review. Consult the original articles before reproducing data in publications, regulated work or redistributed datasets.