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

• Published in: Journal of magnetic resonance (1997) Vol. 259; pp. 76 - 81
• Main Authors: Matsuki, Yoh, Nakamura, Shinji, Fukui, Shigeo, Suematsu, Hiroto, Fujiwara, Toshimichi
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.10.2015
• Subjects: Closed-loop helium circulation; Cold Temperature; Cryogenic magic-angle spinning; Electricity; Helium - chemistry; Magnetic Resonance Spectroscopy - economics; Magnetic Resonance Spectroscopy - instrumentation; Magnetic Resonance Spectroscopy - methods; Sensitivity enhancement; Solid-state NMR; Temperature; Closed-loop helium circulation; Solid-state NMR; Sensitivity enhancement; Cryogenic magic-angle spinning
• ISSN: 1090-7807; 1096-0856
• DOI: 10.1016/j.jmr.2015.08.003

[Display omitted] •Magic-angle spinning (MAS) NMR probe system with a closed-loop helium recirculation.•Stable MAS for weeks at sample temperature T=35K without consuming helium.•Multi-dimensional MAS NMR at T=35K at a low running cost for electricity 16kW/h.•An order of magnitude sensitivity gain at T=40K and B0=16.4T. 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=4–12kHz) at cryogenic temperatures (T=35–120K) for over a week without consuming helium at a cost for electricity of 16kW/h. High-resolution 1D and 2D data were recorded for a crystalline tri-peptide sample at T=40K and B0=16.4T, 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 100K.