title: Improving the hyperpolarization of (31)P nuclei by synthetic design.
abstract: 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.
authors: Centre for Hyperpolarization in Magnetic Resonance, Department of Chemistry, University of York, York YO10 5NY, United Kingdom.
authors: Michael J
authors: MJ
authors: Burns
authors: Centre for Hyperpolarization in Magnetic Resonance, Department of Chemistry, University of York, York YO10 5NY, United Kingdom.
authors: Peter J
authors: PJ
authors: Rayner
authors: Centre for Hyperpolarization in Magnetic Resonance, Department of Chemistry, University of York, York YO10 5NY, United Kingdom.
authors: Gary G R
authors: GG
authors: Green
authors: Centre for Hyperpolarization in Magnetic Resonance, Department of Chemistry, University of York, York YO10 5NY, United Kingdom.
authors: Louise A R
authors: LA
authors: Highton
authors: Centre for Hyperpolarization in Magnetic Resonance, Department of Chemistry, University of York, York YO10 5NY, United Kingdom.
authors: Ryan E
authors: RE
authors: Mewis
authors: Centre for Hyperpolarization in Magnetic Resonance, Department of Chemistry, University of York, York YO10 5NY, United Kingdom.
authors: Simon B
authors: SB
authors: Duckett
mesh_terms: D002250:Carbon Radioisotopes; D004952:Esters / Q000737:chemistry; D006859:Hydrogen / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation / Q000379:methods*; D000432:Methanol / Q000737:chemistry; D015394:Molecular Structure; D019047:Phantoms, Imaging; D010761:Phosphorus Radioisotopes / Q000737:chemistry*; D011522:Protons; D012996:Solutions; D012997:Solvents / Q000737:chemistry
chemical_list: D002250:Carbon Radioisotopes; D004952:Esters; D010761:Phosphorus Radioisotopes; D011522:Protons; D012996:Solutions; D012997:Solvents; D006859:Hydrogen; D000432:Methanol