Improving the hyperpolarization of (31)p nuclei by synthetic design

TY - JOUR

T1 - Improving the hyperpolarization of (31)p nuclei by synthetic design

AU - Burns, Michael J

AU - Rayner, Peter J

AU - Green, Gary G R

AU - Highton, Louise A R

AU - Mewis, Ryan E

AU - Duckett, Simon B

N1 - Copyright © 2015 American Chemical Society. This is an author produced version of a paper published in Journal of Physical Chemistry B. Uploaded with permission from the publisher.

PY - 2015/3/26

Y1 - 2015/3/26

N2 - Traditional (31)P NMR or MRI measurements suffer from low sensitivity relative to (1)H detection and consequently require longer scan times. We show here that hyperpolarization of (31)P nuclei through reversible interactions with parahydrogen 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 (31)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 (31)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. (31)P-hyperpolarized images are also reported from a 7 T preclinical scanner.

AB - Traditional (31)P NMR or MRI measurements suffer from low sensitivity relative to (1)H detection and consequently require longer scan times. We show here that hyperpolarization of (31)P nuclei through reversible interactions with parahydrogen 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 (31)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 (31)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. (31)P-hyperpolarized images are also reported from a 7 T preclinical scanner.

U2 - 10.1021/acs.jpcb.5b00686

DO - 10.1021/acs.jpcb.5b00686

M3 - Article

C2 - 25811635

SN - 1520-6106

VL - 119

SP - 5020

EP - 5027

JO - Journal of Physical Chemistry B

JF - Journal of Physical Chemistry B

IS - 15

ER -