Nuclear Magnetic Resonance Spectroscopy (NMR)

NMR spectrum generated from a 1H-NMR measurement.

Nuclear magnetic resonance spectroscopy (NMR) is a chemical analytical technique used to assay the composition and chemical structure of solutions, solids, mixtures, and macromolecules.

Due to its ability to capture dynamic molecular behavior, it can also be used to characterize reaction kinetics, real-time structural rearrangements, substrate binding and catalysis, and many other processes.

Strengths

Non-invasive and non-destructive (once isotopes are fully integrated)
Can be quantitative when used with reference / control samples
High precision measurement
Optimized for nonselective molecular analysis

Limitations

Sample preparation to use isotopic forms
Less sensitive to composition than mass spectrometry and other chemical analytical techniques
Limited to analyzing NMR-active nuclei

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Example Outputs Instruments Used How NMR Works

Nuclear Magnetic Resonance Spectroscopy Services

Nuclear Magnetic Resonance Spectroscopy

Nuclear magnetic resonance spectroscopy (NMR) is a chemical analytical technique used to assay the composition and chemical structure of solutions, solids, mixtures, and macromolecules.

Due to its ability to capture dynamic molecular behavior, it can also be used to characterize reaction kinetics, real-time structural rearrangements, substrate binding and catalysis, and many other processes.

Sample Requirements

Solid (powders), or liquid / aqueous phase

Example Outputs

NMR spectrum generated from a 1H-NMR measurement. Each peak represents a distinct electrochemical environment surrounding the NMR-active H nuclei; the chemical shifts (x-axis) associated with each peak can be used to identify functional groups present, listed in the top left. Taken together, these shifts then allow experts to characterize the molecular structure of the analyte.

To ensure chemical shift is accurately measured and to allow precise correlative analysis for molecular structure determination, high resolution spectra are captured at each peak. Shown below is a multiplet peak isolated from the above total spectrum, with measured chemical shift and peak-splitting annotations that inform the chemical structure.

Instruments Used

JEOL ECZ500R 500MHz NMR Spectrometer

Magnetic Field Frequency: 500 MHz
Multi-Frequency Drive System: single and multiple nuclei experiments
Control Time Resolution: 5 ns (for phase, amplitude, and frequency modulation)
Wide Dynamic Range: up to 1 : 3,400,00
Sensitivity enhanced by 10% over past NMR systems
Probe Options:
- ROYAL HFX Probe
- SuperCOOL Probe- cools sample to LN2 temperature and improved sensitivity
- 3.2 mm HX MAS Solid-state NMR Probe + Extended Variable Temperature Range
- 3.2 mm HXY MAS Solid-state NMR Probe
- Diffusion NMR probe

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Bruker Avance III HD 600MHz NMR Spectrometer

Magnetic Field Frequency Range: 5 to 650 MHz
Frequency Resolution: < 0.005 Hz
Phase Resolution: < 0.006°
Magnetic Field Strength: 14.1 Tesla
Probe Options:
1. Multinuclear Prodigy CryoProbe – standard liquid samples
  – Temperature Range: -40 °C to +80 °C (for solution state samples only)
2. Bruker SmartProbe – lower-frequency nuclei (as low as 109Ag), 1H/19F decoupling, and correlational (2D / 3D) NMR experiments
  – Temperature Ranger: -150 °C to +150 °C
High-power decoupling up to 15 kHz MAS (for solid-state NMR)

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Bruker Avance III HD 500MHz NMR Spectrometer

Magnetic Field Frequency Range: 5 to 500 MHz
Frequency Resolution: < 0.005 Hz
Phase Resolution: < 0.006°
Magnetic Field Strength: 11 Tesla
Probe: Multinuclear Prodigy CryoProbe and Bruker SmartProbe (same as above)
High-power decoupling up to 15 kHz MAS (for solid-state NMR)

Varian Inova 500 MHz Spectrometer

3 Radiofrequency channels with independent waveform generators
Optimized for 3D NMR experiments on 1H, 13C, 15N nuclei (‘HCN’) and dual-channel broadband experiments
Probe: 5mm Nalorac IDTG Triple-resonance Probe
Temperature Range: -100 °C to +150 °C

How NMR Works

NMR utilizes a strong, static magnetic field along with a weakly oscillating field surrounding the sample to induce and measure changes in the magnetic properties of select atomic nuclei.

Before the NMR measurement, the sample is treated and target atomic species are replaced with electromagnetically active isotopes. The isotopic atoms undergo spin-state polarization in the NMR as the weak field is turned on and off, and the energy and time associated with spin-state relaxation are measured. These values reflect the electromagnetic environment of each isotopically tagged atom; which can be correlated to the overall molecular structure and composition.

Polarization is induced multiple times during a single NMR measurement, and differential field strengths permit 1D- and 2D-analytical modes, in which 1 or 2 atomic species are analyzed serially or simultaneously. This allows for quantitative molecular structure determination, and tracking of dynamic structural changes due to chemical processes.

Most NMR is done with liquid samples; however solid state NMR can be done with specialized equipment. There is also a variation of NMR done at low temperatures.