1 research outputs found
Improving the Hyperpolarization of <sup>31</sup>P Nuclei by Synthetic Design
Traditional <sup>31</sup>P NMR or
MRI measurements suffer from
low sensitivity relative to <sup>1</sup>H detection and consequently
require longer scan times. We show here that hyperpolarization of <sup>31</sup>P nuclei through reversible interactions with <i>para</i>hydrogen can deliver substantial signal enhancements in a range of
regioisomeric phosphonate esters containing a heteroaromatic motif
which were synthesized in order to identify the optimum molecular
scaffold for polarization transfer. A 3588-fold <sup>31</sup>P signal
enhancement (2.34% polarization) was returned for a partially deuterated
pyridyl substituted phosphonate ester. This hyperpolarization level
is sufficient to allow single scan <sup>31</sup>P MR images of a phantom
to be recorded at a 9.4 T observation field in seconds that have signal-to-noise
ratios of up to 94.4 when the analyte concentration is 10 mM. In contrast,
a 12 h 2048 scan measurement under standard conditions yields a signal-to-noise
ratio of just 11.4. <sup>31</sup>P-hyperpolarized images are also
reported from a 7 T preclinical scanner