Deuterium (H2) Detection

Please use the new 400 for H2 detection using the lock channel with the following protocol. This works well with an H2-enriched sample. For best sensitivity if needed, detection through the X-channel is possible.

Note that for the cleanest result, don't use deuterated solvent for detection of D (H2) in your sample. In some cases, however, 10% D-solvent could be used for H2 shimming and locking during the experiment as long as the solvent H2 resonance doesn't interfere with the resonances of your interest.
  1. If 10% deutered solvent is present, try to lock and shim on H2 as usual. Lock signal may be weak. Adjust lock gain and power, or simply click "Lock Find Resonance" button on Start panel for an automatic adjustment.
  2. Enter setexp('H2') to load default H2 detection parameters (using the lock channel). Adjust spectral width and scan numbers (in Acquire panel) and collect and process data as usual.
If your sample doesn't contain deuterated solvent, the experiment has to be run unlocked. You cannot shim on deuterons in this case, which may be Ok if sharpness of the signal isn't of critical interest. Alternatively, you may attempt shimming on a strong H1 signal (in this case it will be the solvent H1 signal. See Manager for steps).
  1. Go to Start->Lock panel and turn lock OFF.
  2. enter alock='n' to turn off autolock adjustment at the start of the experiment.
  3. Enter setexp('H2') to load default H2 detection parameters (using the lock channel). Adjust spectral width and scan numbers (in Acquire panel) and collect and process data as usual.

Referencing H2 Spectrum

If a solvent H2 signal is present in the spectrum, you can use it to reference the spectrum manually just like for H1 spectrm. If not or ambigous, as a valid alternative method, you can also use a referenced H1 spectrum from this sample, collected within the same brief period, to indirectly reference the H2 (or any other) sprectrum.
  1. Using a separate experiment setup (a different exp. number), i.e. under exp2 if the H2 spectrum is under exp1, collect a H1 spectrum and reference it properly.
  2. Go to the H2 spectrum (i.e. use jexp1 if it is under exp1). Then, enter mref(2,1) to reference exp1 (H2 spectrum in this case) using the reference present in exp2. Change exp# according to your situation.

The following applies to H2 detection using the 500.
Deuterium has similar chemical shifts as H1 but its bandwidth in Hz is 7 times smaller (~1600 Hz at 500Mhz) which makes it easier to excite. Accurate integration is achievable. Deuterium detection can be done in one of two ways with wildly different sensitivity, depending on the probe:

  1. Recommended: On a broadband probe (such as SWP on nmr500), the best signal is obtained via pulsing/detection through the broadband X-channel similar to other X-nucleus detection with small cabling changes.
  2. On most probes including an indirect detection probe (such as IDP of nmr400), you can also use the lock channel for H2 detection, albeit with much lower sensitivity depending on probe design. On an IDP probe, pulsing through X-channel is not possible.

In both cases, run the experiment unlocked although a lock diplexer (available on nmr500) offers a choice of locking in between scans when not pulsing if the 2nd method is used.

Sample preparation

In general, two samples of identical sample volume (~700uL) with the same solvent (one with 10% deuteration) are recommended.

Sample 1:

Sample 2:

Procedure for using the X-channel of SWP on nmr500

Step 1: Lock and shim with Sample 1.

Step 2: Set up H2 detection experiment

Step 3: Recable and tune X-channel

Step 4: Optional: Test H2 detection with 10% deuterated solvent signal

Step 5: Run actual experiment with sample 2

Step 6: Finishing up: recable and tune X-channel for C13

H. Zhou updated Dec 2010