PNNL-13501 - Pacific Northwest National Laboratory

of technology, it is anticipated that NMR has a limited
role. If NMR spectroscopy is to contribute significantly
to this effort, then the data collection time for the NMR
experiment must be dramatically reduced, and the
applicable molecular weight range must be expanded to
>100 kDa.
Given the existence of high field (>17 T magnets) NMR
spectrometers, why does it take so long to collect the
critical data sets? A significant recent advance is the
introduction of cryoprobe technology in which the NMR
coil and preamplifier are cooled to near liquid helium
temperatures. This advance, that can theoretically
increase NMR sensitivity by a factor of 3 to 4, holds the
prospect of reducing NMR data collections times by as
much a factor of 10. However, cryoprobe performance
will reach a practical limit at high fields because of the
consequences of the dielectric losses of the sample on
NMR sensitivity. If the sample losses could be
significantly reduced, the sensitivity would increase and
optimal cryoprobe performance could be obtained.
Virtually all proteins require water as a solvent in the
presence of varying concentrations of salts (typically