Closed-cycle cold helium magic-angle spinning for sensitivity-enhanced multi-dimensional solid-state NMR

J Magn Reson. 2015 Oct:259:76-81. doi: 10.1016/j.jmr.2015.08.003. Epub 2015 Aug 12.

Abstract

Magic-angle spinning (MAS) NMR is a powerful tool for studying molecular structure and dynamics, but suffers from its low sensitivity. Here, we developed a novel helium-cooling MAS NMR probe system adopting a closed-loop gas recirculation mechanism. In addition to the sensitivity gain due to low temperature, the present system has enabled highly stable MAS (vR=4-12 kHz) at cryogenic temperatures (T=35-120 K) for over a week without consuming helium at a cost for electricity of 16 kW/h. High-resolution 1D and 2D data were recorded for a crystalline tri-peptide sample at T=40 K and B0=16.4 T, where an order of magnitude of sensitivity gain was demonstrated versus room temperature measurement. The low-cost and long-term stable MAS strongly promotes broader application of the brute-force sensitivity-enhanced multi-dimensional MAS NMR, as well as dynamic nuclear polarization (DNP)-enhanced NMR in a temperature range lower than 100 K.

Keywords: Closed-loop helium circulation; Cryogenic magic-angle spinning; Sensitivity enhancement; Solid-state NMR.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cold Temperature
  • Electricity
  • Helium / chemistry*
  • Magnetic Resonance Spectroscopy / economics
  • Magnetic Resonance Spectroscopy / instrumentation
  • Magnetic Resonance Spectroscopy / methods*
  • Temperature

Substances

  • Helium