Running NMR experiments on deuterium (2H)
as the observed nucleus is slightly different than most other nuclei.
The DCIF has two instruments suited for observing deuterium:
The Varian Inova 501 (known as Rocky)
The Varian Inova 500 (known as Bullwinkle)
These experiments are often run 'unlocked' as these experiments are
typically performed in a non-deuterated solvent. Fortunately, you
should still be able to reference your spectrum to the naturally
abundant deuterium in the solvent. Simply look in the 'grass' and you
should find the reference peak(s). Another consideration is 'cross
talk'. In order to minimize the rf 'cross talk' between channels we
recommend you disconnect the lock cable before submitting the
experiment. The tuning procedures for both of these instruments are as
2H-NMR on the Varian Inove 501 (Broadband probe) & Varian 500 (Inverse Probe)
NOTE: If you want to shim the magnet, do so first with appropriate
proton parameters loaded, before starting deuterium (which will require
that the lock channel be removed).
Load parameters for deuterium/solvent.
Insert the sample.
Close the acqi window.
Tuning the probe to 2H:
You will need to tune (or at least check) for each sample.
- Turn the tune counter to 54.
- Insert the appropriate (7 pF) capacitor stick (labeled 2H).
- Disconnect lock channel cable from probe.
- Remove lock filter.
- Replace the 13C-bandpass filter with the 2H-bandpass filter.
- Move cables as usual (tune with filter in line) probe to probe; output to output.
- Tune and match as usual.
When finished, you will need to tune back to 13C: (Leave sample inserted to tune back to carbon.)
Load parameters for 13C/solvent.
Close acqi window.
Tuning the probe back to 13C:
- Remove the capacitor stick (return to tube on top of console)
- Turn tune-counter to 35.
- Re-connect lock channel.
- Replace lock filter.
- Replace the 13C-bandpass filter. (Place the other to the top of console along with the others)
- Move cables and tune as usual.
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