Cryocoil magic-angle-spinning solid-state nuclear magnetic resonance probe system utilized for sensitivity enhancement in multiple-quantum magic-angle-spinning spectroscopy for a low-γ quadrupolar nucleus of 85Rb

Sensitivity enhancement in solid-state nuclear magnetic resonance using a cryocoil magic-angle spinning system was investigated, by comparing, at room temperature and at cryogenic temperature, the signal-to-noise ratios of the multiple-quantum magic-angle-spinning spectra as well as the conventional spectra for a low-gamma nucleus Rb-85 in RbNO3. The increase of the sample-coil quality-factor and the thermal noise reduction were found to enhance the sensitivities by approximately 4.5 times; the former yielded the further doubled signal increase in the multiple-quantum spectroscopy via the increase of the radio-frequency field strengths. Eventually, 20-30 times of the sensitivity enhancement were realized in the two-dimensional multiple-quantum magic-angle-spinning spectra. (C) 2017 Elsevier B.V. All rights reserved.