Solid State NMR (SSNMR)

NMRFAM is greatly expanding its solid-state NMR capabilities in 2020, with five spectrometers being installed and upgraded with consoles, amplifiers and magic-angle spinning (MAS) probes. Capabilities already or will soon include 13C-detection at moderate (up to 25 kHz) MAS rates, 1H-detection at MAS rates up to 60 kHz, REDOR (including 31P and 19F), and oriented sample (PISEMA) experiments. Staff are available to support collection of multidimensional data sets at fields ranging from 600 to 900 MHz, as well as support for data analysis and interpretation. NMRFAM is also adding substantial capabilities to study broadband nuclei including quadrupolar nuclei, in support or applications to chemistry, materials science and engineering. Please stay tuned to the NMRFAM SSNMR page for updates as instruments come fully online.

Biological SSNMR

Solid state NMR (SSNMR) spectroscopy is used for studying wide range of biomolecular systems such as crystalline proteins, fibrillar proteins, membrane proteins, as well as concentrated soluble and sedimented protein samples. For SSNMR analysis, isotopically labeled (13C and 15N) protein samples are centrifugated to obtain hydrated pellets that are packed into MAS (magic angle spinning) rotors. The sample in the rotor is spun at magic angle axis, i.e., 54.7o with respect to Bo field (z-axis). The maximum spinning frequency is inversely proportional to the probe rotor diameter, and therefore requires distinct MAS probe for achieving different range of spinning speeds. Protein structural data is obtained by using 13C and/or 1H detected experiments. For 13C detected experiments, typical MAS rotor diameter sizes are 1.6 mm and 3.2 mm with respective sample volumes, 10 and 25 µl. Under these conditions 13C detected experiments are acquired with MAS rates of 10 to 35 kHz. On the other hand, 1H-detected experiments require ultrafast and very fast MAS probes with smaller rotor diameters, such as 1.3 mm and 0.7 mm with respective samples volumes, 3 and 1 µl, and MAS rates of 60 to 100 kHz are used. For 1H-diluted or perdeuterated protein samples, 1H detected experiments are acquired using fast MAS (1.6 mm) or ultrafast (1.3 mm) MAS probes using MAS rates of 30 to 60 kHz.

Materials SSNMR

Solid-state NMR can be useful for the study of a wide variety of materials; but because of the breadth of this range, it can be difficult to immediately assess whether NMR is the right tool for the question that is being asked. NMRFAM is happy to discuss your specific proposal regardless of your chemistry and sample, but please look over the following information before reaching out to us so that you have an idea of the difficulty of your proposal.

· Samples must not be conductive or ferromagnetic.

· Paramagnetic samples present serious, but not necessarily insurmountable, challenges.

· Samples that are highly toxic or radioactive do not necessarily pose NMR problems, but are a safety hazard, and will not be accepted.

The nucleus being studied by NMR often has a larger impact on the proposed experiment than the exact chemistry. When thinking about an experiment, consult the periodic table below for an idea of the challenges associated with your target nucleus.

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· No concerns about sensitivity
· MAS rates achievable with standard probes
· Widely used in the literature
· No isotopic enrichment required
· Compatible with most pulse sequences


· Concerns about sensitivity
· Isotopic enrichment may be required
· May require larger rotors than currently available at NMRFAM
· Widely used in the literature
· Compatible with many, but not necessarily all, pulse sequences


· Serious sensitivity issues
· Isotopic enrichment may be required
· Sensitivity enhancement techniques are recommended
· MAS may not be possible or useful
· Compatible with limited set of pulse sequences
· Examples in the literature, but not widely studied


· Potentially prohibitive sensitivity issues
· Isotopic enrichment recommended where feasible
· Large quadrupole moments may prevent acquisition of useful spectra
· Potential safety issues from samples
· Spectra may only be available from limited set of chemistries
· Only very simple pulse sequences are viable
· NMRFAM equipment may not support this nucleus


· NMR-active isotopes may not exist
· NMR-active isotopes may be radioactive
· Nuclear properties may prohibit acquisition of spectra