Solvents

For 1H experiments protio-solvent should be avoided, if possible, as the strong solvent signals will interfere with the spectrum required. The solvent should normally contain a strong deuterium signal (e.g. CDCl3) so that the field can be "locked" for the duration of the experiment. This is especially important for 1H measurements where good resolution is required.

All of the spectrometers have an option for running samples unlocked (i.e. without d-solvent) but this usually only appropriate with certain 31P or 11B measurements. Solvent suppression experiments can sometimes be used to reduce residual solvent signals in 1H spectra (see 1D experiments guide).

Solvent Supplies

In general, NMR lab DOES NOT provide deuterated solvents.

If you have urgent requirements, you may contact NMR staff for assistance.


Solvent Signals

Please see Cambridge Isotope Laboratories chart for Chemical Shifts, boiling points etc. of NMR solvents (courtesy of Cambridge Isotope Laboratories).

Referencing

All NMR spectra run by the service are calibrated in the ppm scale.

For 1H, 2H and 13C internal TMS is the accepted reference (0 ppm), and this is used whenever its signal can be observed in the sample.

For all other nuclei (or samples without TMS), spectra are referenced via the deuterated solvent against the magnet field and hence known reference compounds. The reference substances (0ppm) for the more common nuclei are as follows:


11B      BF3.OEt2

29Si     TMS

7Li       1M LiCl in H2O

51V      VOCl3

19F       CCl3F

17O      H2O

31P      85% Phosphoric acid (H3PO4)

23Na    1M NaCl in H2O

195Pt    Na2PtCl6

15N      MeNO2


(these should be quoted as 'external references')