Small molecule NMR sample preparation

  1. If just collect 1D proton and 1D carbon spectra, (say, your small molecule’s MW: ~400 Da), 10 to 20 mg/ml concentration (corresponding to 25 to 50 mM) and 0.5 to 0.6 ml volume is very normal.
  2. Use deuterated solvents, e.g., CDCl3-d, DMSO-d6, etc. to prepare your nmr samples, this is for NMR locking and shimming purpose and avoiding solvent proton peaks.
  3. Use 5-mm outer diameter, 7- or 8-inches length nmr tubes. You can buy from our VWR storeroom or order online from NORELL with item#: S-5-500-7. (our B800-Luke NMR machine needs 3-mm tubes with item# : S-3-800-7).
  4. Don’t use very “old”, glass-wall scratched, chipped, or top-fractured tubes.
  5. Don’t use ultrasonic bath cleaner to wash your nmr tubs, otherwise the nmr tubes will be getting fragile and may be broken when you insert your nmr sample tube; don’t use lab oven to dry nmr tubes, after cleaning the solid deposit, use plenty of water through a long glass pipette to flush the nmr tube inner bottom for 1 to 2 minutes and lay down on a tray and air dry it.
  6. Fully push the nmr cap onto the tube top, don’t use paper tape to label on your nmr tube.

Hongwei edited on 8/29/2023