Solid-State Capabilities & Techniques
A list of solid-state capabilities and techniques is below; please click on the links for more details on these techniques.
Double- and triple-resonance static Low-E probes with sample coils for both flat and bicelle sample preparations are available at 900, 720, 600, and 400 MHz. Observations of orientational constraints from PISEMA or similar non-spinning experiments are used for structure determination in membrane proteins. Low frequency probe channels are configurable to desired nuclei.
Sensitive triple-resonance Low-E 1HXY MAS probes are available to users at 900, 800 and 600 MHz. The Low-E technology was developed at the MagLab to provide maximum sensitivity of direct detection in CP and double-CP experiments, while protecting biological samples from rf-induced heating. A suite of 2D and 3D MAS experiments (DARR, NCA, NCO, NCOCX, etc.) allows for spectral assignment and structural elucidation of labeled proteins. Several 1HXY detection modes are available.
Double rotation (DOR) spins a small inner rotor inside a larger outer rotor. The simultaneous sample rotation about the two axes leads directly to isotropic high-resolution spectra of half-integer quadrupolar nuclei.
19F is the most sensitive NMR nucleus besides 1H and its chemical shift is extremely sensitive to local electrostatic and van der Waals environments.
Powered magnets using conventional conductor and water cooling can generate magnetic fields much higher than superconducting magnets. These magnets can be ramped quickly and continuously and are accessible at the MagLab for ultrahigh field NMR spectroscopy (note small degrees of field inhomogeneity and fluctuation need be tolerated and the time duration of operation is limited as compared to 7/24 operation of more homogeneous and stable conventional superconducting NMR magnets).
In situ NMR of electrochemical cells can be performed at 400 MHz with this specially constructed static probe. The Low-E feature helps to sustain 1H decoupling in the presence of lossy electrolytes. A specially constructed in situ STRAFI probe at 830 MHz can be used for real time monitoring of the electrodes at a micron level
Moderate to low temperature range is available at 900 MHz for studies of phase transitions and molecular dynamics. The 1HX broadband transmission line MAS probe has a temperature range down to -140°C depending on spinning speed.
DNP has been demonstrated to increase the sensitivity of NMR experiments by several orders of magnitude, which can lead to additional information about the systems being studied and drastically reduce experimental acquisition times.
Central transitions of half-integer quadrupolar nuclei are broadened by second-order quadrupolar shift even under magic angle spinning (MAS). High magnetic fields are effective reducing the quadrupolar broadening achieving high spectral resolution and sensitivity.
Magic-angle sample spinning (MAS) is the standard method for obtaining high-resolution NMR spectra of solids. In the presence of strong dipolar-dipolar couplings such as protons in solids, faster spinning averages out more effective the dipolar broadening. MAS probes with spinning speed up to 70kHz (1.3mm rotor diameter) are available at 800MHz MB and 600MHz WB instruments. The ultrafast MAS is useful for direct proton detection of solid samples.