Is there a submission form to fill out when I drop off my samples?
Yes, we have one form for University of Guelph users and another for external groups (companies, other universities, etc.).
How do I view and process my data on my lab or personal computer?
The New Users' Guide also describes how to download your NMR data and how to install a free, academic version of Topspin 4.0 from Bruker.
What are "best practices" for preparing NMR samples?
- Tube: Use only an allowed NMR tube (Wilmad 506-PP) that is not chipped or cracked.
- Concentration: 1-2 mg/mL for 1H NMR, and 20-50 mg/mL for 13C NMR. Don't make samples too concentrated, especially when using the 600 MHz cryoprobe. Overconcentrated samples may suffer from "radiation damping" which distorts peakshapes and baselines.
- Preparation: Dissolve (or mix) your sample in the solvent of choice in a vial, add any desired internal standard, and mix very thoroughly before transferring to the NMR tube. If necessary, filter the sample to remove insoluble particles. (Dissolving/mixing directly in the NMR tube will lead to terrible lineshapes, while insoluble particles can also degrade lineshapes.)
- Volume: Too little and the lineshape/shims will be poor, but too much and there can be issues/artifacts from sample convection, especially with cryoprobes.
- When using the cryoprobe, the volume in the tube should be 560 uL.
- For other probes (e.g. 300 MHz, 600 MHz in MacN), between 600-650 uL is fine.
- If you are using a volatile solvent (e.g. CDCl3, DCM) and are running long experiments, be mindful of sample evaporation during your experiment.
- For 3 mm NMR tubes, use 200 uL.
- Aqueous (H2O) samples: Ensure that there is at least 5-10% D2O in the sample for spectrometer lock.
- Organic solvent samples: Some solvents (e.g. DMSO and D2O) are more likely to take on H2O from the atmosphere, leading to an intense water peak in the NMR spectrum. To reduce this, prepare a sample using a fresh vial of deuterated solvent and then wrap the sample tube cap with parafilm.
What kind of NMR tube should I use?
Only Wilmad or Shigemi brand tubes are allowed in the NMR Centre. Wilmad tubes must be of grade 506-PP or higher. Please contact NMR staff prior to using any other kind of tube (e.g. sealed tubes).
The tube must not be chipped, cracked, or warped in any way or else it could damage or break in the probe (costing thousands of dollars to repair). New tubes can be purchased from Chemistry Stores (in Science Complex) or by contacting NMR staff.
(Aside - don't bake your tubes in a hot oven to dry, or they may warp. If it is necessary to dry them, use a 70 C oven, and lay them flat.)
How should I clean my NMR tube?
Use an NMR tube washer to rinse the tube with at least three volumes of the same (non-deuterated) solvent. Then, rinse one final time with a low boiling point solvent (e.g. acetone). Dry the tubes by laying them flat in a 70 C oven. Avoid higher temperatures which may warp the tubes (warpage of even a few micrometers can cause breakage inside the NMR probe).
For biomolecular aqueous samples, soak the tubes overnight in 5% HNO3, then rinse with multiple volumes of water until the pH of the rinsate is netural. If a film remains in the NMR tube, let the tubes soak in 1 M NaOH for one hour, then repeat the HNO3 and rinsing steps. Do not use stronger NaOH or longer times or else you will etch the tubes. Dry the tubes as described above.
How did you get the 800 into the lab?
A large opening was made in the side of the Science Complex, directly into the nearby AAC staff lounge. Large double-doors were installed in the lounge and the NMR lab, allowing the magnet to be brought in.