Sample Preparation Do not use chipped or cracked NMR tubes Use 507PP or 528PP NMR tubes on the Varian instruments to prevent damage to the probes. The NMR lab does not provide solvents for your use. Standard shims are determined on a sample 50mm in height. Shorter samples will require additional time to shim. Longer samples waste solvent and dilute the concentration.
Separate training is required for variable temperature work.
Be aware of the temperature limitations on the probe you are using. Always use new 528 NMR tubes for VT work. Old tubes may be scratched and more likely to break. For variable temperature work, you must schedule enough instrument time to bring the temperature back to room temperature when you are finished. Weekend restrictions in effect on all spectrometers 4.