LimsPulse
Spectroscopy

Nuclear magnetic resonance (NMR) spectrometer

Places a sample in a strong magnetic field and measures how atomic nuclei such as ¹H and ¹³C absorb radio waves. Gives detailed structural information and, with qNMR, absolute purity without a reference standard of the analyte.

  • Pharmaceutical
  • Biotech
  • Chemicals
  • Academia & research
  • Food (authenticity)
  • Petrochemical
Photo of a Nuclear magnetic resonance (NMR) spectrometer
Photo: Sarka Na kopci, CC BY-SA 4.0 (cropped), via Wikimedia Commons
Follow your site SOP
This is a typical operating sequence for learning. Your instrument model and approved SOP take precedence.
STAGE 1

Before you start

  1. 1Check you are trained and authorised for the NMR room and that the instrument's performance checks are current.
  2. 2Remove all magnetic items, credit cards, watches and phones before entering the 5 gauss line.
  3. 3Prepare the sample: dissolve the weighed material in the stated volume of deuterated solvent (often about 0.6 mL for a 5 mm tube) and filter if cloudy.
  • People with pacemakers or metal implants must not enter the 5 gauss zone.
STAGE 2

Acquiring a spectrum

  1. 1Wipe the tube, fit the spinner and set the depth with the depth gauge.
  2. 2Insert the sample, then lock on the solvent and shim (automatic routines are normal).
  3. 3Tune and match the probe for the nucleus.
  4. 4Load the approved parameter set (pulse angle, relaxation delay, number of scans) and acquire.
  • For qNMR use the validated parameters: 90° pulse, long relaxation delay and enough scans for a signal-to-noise of typically at least 150:1 on the signals used.
STAGE 3

Processing and reporting

  1. 1Fourier transform, then correct phase and baseline.
  2. 2Reference the spectrum (e.g. TMS at 0.00 ppm or the residual solvent signal).
  3. 3Integrate signals and assign them to the structure, or compare with the reference spectrum.
  4. 4For qNMR, integrate the chosen analyte and internal standard signals and calculate purity.
STAGE 4

Finishing

  1. 1Eject the sample and remove it from the spinner.
  2. 2Dispose of deuterated solvents as chemical waste; clean or discard tubes.
  3. 3Complete the instrument log, including any helium or nitrogen level readings required.
In LimsPulse · Calibration Management

Keep every NMR in control: usage logs, calibration and maintenance schedules, and automatic blocking of overdue instruments.

See how