NMR impurities in CD₃OD

Common impurity peaks observed in CD₃OD (solvent residual ¹H: 3.31 (quint); ¹³C: 49.00). Full solvent residual table: NMR solvent residual peaks.

Trace solvents, drying agents, and workup residues often appear as extra signals beside your compound. The tables below list typical ¹H chemical shifts (δ, ppm) reported for common impurities in each deuterated solvent. Values are taken from the Gottlieb (1997) and Fulmer (2010) compilations (DOI 10.1021/jo971176v, 10.1021/om100106e). Shifts drift slightly with temperature, concentration, and water content—compare nearby runs on the same instrument when assigning peaks.

To reduce impurity signals: use fresh solvent, avoid silicone grease near the NMR tube, dry glassware, and remove volatile solvents (EtOAc, DCM, ether, THF) on a rotary evaporator before dissolving the sample. Residual water appears at solvent-dependent chemical shifts; see the water-in-solvents table on the solvent residual peaks page.